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157-511: Lake Chelan NRA is adjacent to the North Cascades National Park South Unit. There are no roads that lead into Lake Chelan NRA. The recreation area and Stehekin , a small town in the park with fewer than 100 permanent residents, are accessible only by floatplane or passenger ferry from the south end of Lake Chelan near the town of Chelan, Washington . The area can also be accessed by hiking trails through

314-666: A collapse of an underlying weak snow layer, and loose snow avalanches made of looser snow. After being set off, avalanches usually accelerate rapidly and grow in mass and volume as they capture more snow. If an avalanche moves fast enough, some of the snow may mix with the air, forming a powder snow avalanche . Though they appear to share similarities, avalanches are distinct from slush flows , mudslides , rock slides , and serac collapses. They are also different from large scale movements of ice . Avalanches can happen in any mountain range that has an enduring snowpack. They are most frequent in winter or spring, but may occur at any time of

471-424: A critical temperature gradient. Large, angular snow crystals are indicators of weak snow, because such crystals have fewer bonds per unit volume than small, rounded crystals that pack tightly together. Consolidated snow is less likely to slough than loose powdery layers or wet isothermal snow; however, consolidated snow is a necessary condition for the occurrence of slab avalanches , and persistent instabilities within

628-412: A diversity of animal species including 75 mammal species. A total of 18 species of carnivores including coyote , bobcat , lynx , cougar , mink , river otter and black bear have been reported within this park. Several species of deer such as the elk and moose , several more species of bovids including the mountain goat and bighorn sheep , and more than two dozen species of rodents like

785-559: A drag force that was proportional to the square of the speed of its flow: He and others subsequently derived other formulae that take other factors into account, with the Voellmy-Salm-Gubler and the Perla-Cheng-McClung models becoming most widely used as simple tools to model flowing (as opposed to powder snow) avalanches. Since the 1990s many more sophisticated models have been developed. In Europe much of

942-642: A food source for birds such as the Clark's nutcracker and mammals including red and Douglas squirrels . Scientists believe that increasing temperatures will have a negative impact on the habitat necessary to support whitebark pine, and therefore impact a wide array of other species. White pine blister rust and mountain pine beetles have devastated whitebark pine populations in many regions; as of 2018, "28 percent of whitebark pine trees are dead, 30 percent are infected with blister rust, and 1 percent have died from mountain pine beetles." This park has

1099-463: A fracture at the bottom called the stauchwall. The crown and flank fractures are vertical walls in the snow delineating the snow that was entrained in the avalanche from the snow that remained on the slope. Slabs can vary in thickness from a few centimetres to three metres. Slab avalanches account for around 90% of avalanche-related fatalities. The largest avalanches form turbulent suspension currents known as powder snow avalanches or mixed avalanches,

1256-440: A government-sponsored exploration that traversed the western boundary of the southern section of the current park, in search of transportation routes and natural resources. As with the party led by McClellan in the 1850s, Pierce failed to find a suitable route for a railway, and only marginally suitable routes for roads. However, the expedition discovered gold in a quartz vein on the slopes of Eldorado Peak . Further expeditions by

1413-450: A kind of gravity current . These consist of a powder cloud, which overlies a dense avalanche. They can form from any type of snow or initiation mechanism, but usually occur with fresh dry powder. They can exceed speeds of 300 km/h (190 mph), and masses of 1,000,000 tons; their flows can travel long distances along flat valley bottoms and even uphill for short distances. In contrast to powder snow avalanches, wet snow avalanches are

1570-607: A long term, lasting from days to years. Experts interpret the recorded data and are able to recognize upcoming ruptures in order to initiate appropriate measures. Such systems (e.g. the monitoring of the Weissmies glacier in Switzerland ) can recognize events several days in advance. Modern radar technology enables the monitoring of large areas and the localization of avalanches at any weather condition, by day and by night. Complex alarm systems are able to detect avalanches within

1727-411: A low velocity suspension of snow and water, with the flow confined to the track surface (McClung, 1999, p. 108). The low speed of travel is due to the friction between the sliding surface of the track and the water saturated flow. Despite the low speed of travel (≈10–40 km/h), wet snow avalanches are capable of generating powerful destructive forces, due to the large mass and density. The body of

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1884-599: A northern and a southern district or unit. These are separated by Ross Lake National Recreation Area. The southeast boundary of the southern district abuts Lake Chelan National Recreation Area; the park and two recreation areas are managed as the North Cascades National Park Complex. Most of the park complex was designated as the Stephen Mather Wilderness, preventing further human-induced alterations to 93 percent of

2041-400: A number of methods including hand-tossed charges, helicopter-dropped bombs, Gazex concussion lines, and ballistic projectiles launched by air cannons and artillery. Passive preventive systems such as snow fences and light walls can be used to direct the placement of snow. Snow builds up around the fence, especially the side that faces the prevailing winds . Downwind of the fence, snow build-up

2198-413: A persistent weakness in the snowpack. When a slab lying on top of a persistent weakness is loaded by a force greater than the strength of the slab and persistent weak layer, the persistent weak layer can fail and generate an avalanche. Any wind stronger than a light breeze can contribute to a rapid accumulation of snow on sheltered slopes downwind. Wind slabs form quickly and, if present, weaker snow below

2355-400: A point significantly above the freezing point of water, may cause avalanche formation at any time of year. Persistent cold temperatures can either prevent new snow from stabilizing or destabilize the existing snowpack. Cold air temperatures on the snow surface produce a temperature gradient in the snow, because the ground temperature at the base of the snowpack is usually around 0 °C, and

2512-412: A point with only a small amount of snow moving initially; this is typical of wet snow avalanches or avalanches in dry unconsolidated snow. However, if the snow has sintered into a stiff slab overlying a weak layer, then fractures can propagate very rapidly, so that a large volume of snow, possibly thousands of cubic metres, can start moving almost simultaneously. A snowpack will fail when the load exceeds

2669-662: A portion of the southern district of the park, to the southwest. Along the southwest border is Wenatchee National Forest , within which lies the Glacier Peak Wilderness . The southern boundary of the park is shared with Lake Chelan NRA, and a small section of the eastern boundary is shared with the Okanogan–Wenatchee National Forest . The Lake Chelan-Sawtooth Wilderness lies in the Okanogan–Wenatchee National Forest along

2826-451: A series of flumes , the longest of which was over 3 miles (4.8 km), to transport lumber and to supply water for use in their hydraulic mining operation. During the late 19th century and the first half of the 20th century, larger operations mined silver and lead in addition to gold, mostly with little or no profitability. The demand for metals was not constant, and so prices tended to fluctuate too greatly for mining to be viable. Once

2983-592: A short time in order to close (e.g. roads and rails) or evacuate (e.g. construction sites) endangered areas. An example of such a system is installed on the only access road of Zermatt in Switzerland. Two radars monitor the slope of a mountain above the road. The system automatically closes the road by activating several barriers and traffic lights within seconds such that no people are harmed. Avalanche accidents are broadly differentiated into 2 categories: accidents in recreational settings, and accidents in residential, industrial, and transportation settings. This distinction

3140-525: A significant influence on river levels, accounting for about 30 percent of the late summer water flow, which directly impacted the supported ecosystems such as salmon fisheries. The National Park Service, United States Geological Survey (USGS) and glaciologists such as Mauri S. Pelto , who has led the North Cascades Glacier Climate Project since 1984, have continued research on North Cascade glaciers. Since 1993,

3297-417: A start zone where the avalanche originates, a track along which the avalanche flows, and a runout zone where the avalanche comes to rest. The debris deposit is the accumulated mass of the avalanched snow once it has come to rest in the run-out zone. For the image at left, many small avalanches form in this avalanche path every year, but most of these avalanches do not run the full vertical or horizontal length of

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3454-415: A storm. Daytime exposure to sunlight will rapidly destabilize the upper layers of the snowpack if the sunlight is strong enough to melt the snow, thereby reducing its hardness. During clear nights, the snowpack can re-freeze when ambient air temperatures fall below freezing, through the process of long-wave radiative cooling, or both. Radiative heat loss occurs when the night air is significantly cooler than

3611-412: A sufficient quantity of airborne snow, this portion of the avalanche can become separated from the bulk of the avalanche and travel a greater distance as a powder snow avalanche. Scientific studies using radar , following the 1999 Galtür avalanche disaster , confirmed the hypothesis that a saltation layer forms between the surface and the airborne components of an avalanche, which can also separate from

3768-727: A three-month period throughout the Alps in Austria, France, Switzerland, Italy and Germany. This series of avalanches killed around 265 people and was termed the Winter of Terror . A mountain climbing camp on Lenin Peak, in what is now Kyrgyzstan, was wiped out in 1990 when an earthquake triggered a large avalanche that overran the camp. Forty-three climbers were killed. In 1993, the Bayburt Üzengili avalanche killed 60 individuals in Üzengili in

3925-413: A variety of factors such as the snow's shear strength (which is itself dependent upon crystal form) and the configuration of layers and inter-layer interfaces. The snowpack on slopes with sunny exposures is strongly influenced by sunshine . Diurnal cycles of thawing and refreezing can stabilize the snowpack by promoting settlement. Strong freeze-thaw cycles result in the formation of surface crusts during

4082-833: Is Black Peak (8,970 ft (2,730 m)). Other prominent peaks in the southern section of the park include Boston Peak (8,894 ft (2,711 m)), Eldorado Peak (8,868 ft (2,703 m)) and Forbidden Peak (8,815 ft (2,687 m)). The northern region of the park contains the Picket Range , a subrange of the Skagit Range , which is in turn a subrange of the North Cascades. The Picket Range has numerous spires with ominous names such as Mount Fury , Mount Challenger , Poltergeist Pinnacle , Mount Terror , Ghost Peak and Phantom Peak , all of which exceed 8,000 ft (2,400 m). The Picket Range

4239-629: Is a national park of the United States in Washington . At more than 500,000 acres (200,000 ha), it is the largest of the three National Park Service units that comprise the North Cascades National Park Complex. North Cascades National Park consists of a northern and southern section, bisected by the Skagit River that flows through the reservoirs of Ross Lake National Recreation Area . Lake Chelan National Recreation Area lies on

4396-555: Is a prime habitat for grizzly bear, but the species was extirpated from the region by 1860. Only two grizzly bear sightings occurred in the decade before 2015, and these were outside the park boundary in Canada. In 1991, a decision was reached by the Interagency Grizzly Bear Committee, a US Government land management agency committee, to make efforts to restore self-sustaining populations of grizzlies in

4553-403: Is a rigid fence-like structure ( snow fence ) and may be constructed of steel , wood or pre-stressed concrete . They usually have gaps between the beams and are built perpendicular to the slope, with reinforcing beams on the downhill side. Rigid barriers are often considered unsightly, especially when many rows must be built. They are also expensive and vulnerable to damage from falling rocks in

4710-507: Is allowed. Human history in North Cascades National Park and the surrounding region begins 8–10,000 years ago, after the end of the last glacial period . Paleo-Indians slowly advanced from Puget Sound into the interior mountain region as the glacial ice retreated. Archaeological evidence from other sites hundreds of miles away from the park indicate that Hozomeen chert , a type of rock well-suited to

4867-739: Is between June and September. Ross Lake NRA is easily accessible on State Route 20 (also called the North Cascades Highway), the only road which traverses the park complex; the highway lies entirely within the Ross Lake NRA. Only two primitive roadways enter the actual national park. The North Cascades National Park Complex had an operating base budget of $ 7,700,000 for fiscal year 2010, augmented by another $ 3,700,000 of non-base funding (which can fluctuate significantly on an annual basis), and additional funding from revenue generated from concessionaire contracts and user fees. Much of

Lake Chelan National Recreation Area - Misplaced Pages Continue

5024-579: Is called the Starting Point and typically occurs on a 30–45 degree slope. The body of the pathway is called the Track of the avalanche and usually occurs on a 20–30 degree slope. When the avalanche loses its momentum and eventually stops it reaches the Runout Zone. This usually occurs when the slope has reached a steepness that is less than 20 degrees. These degrees are not consistently true due to

5181-513: Is comparable to much taller mountain ranges. The tallest mountain in North Cascades National Park is Goode Mountain at 9,220 ft (2,810 m). It lies in a remote backcountry region of the southern section of the park. Nearby are several other peaks that exceed 9,000 ft (2,700 m), including Buckner Mountain (9,114 ft (2,778 m)) and Mount Logan (9,087 ft (2,770 m)). At about 9,000 ft (2,700 m), about 5 miles (8.0 km) northeast of Goode Mountain,

5338-424: Is critically sensitive to small variations within the narrow range of meteorological conditions that allow for the accumulation of snow into a snowpack. Among the critical factors controlling snowpack evolution are: heating by the sun, radiational cooling , vertical temperature gradients in standing snow, snowfall amounts, and snow types. Generally, mild winter weather will promote the settlement and stabilization of

5495-408: Is flat enough to hold snow but steep enough to ski has the potential to generate an avalanche, regardless of the angle. The snowpack is composed of ground-parallel layers that accumulate over the winter. Each layer contains ice grains that are representative of the distinct meteorological conditions during which the snow formed and was deposited. Once deposited, a snow layer continues to evolve under

5652-479: Is influenced by the great vertical relief, the amount of moisture an area receives, the slope and soil types as well as the fire ecology . This wide array of ecological niches has allowed a great biodiversity to evolve. Few other North American national parks have recorded as many vascular plant species as have been documented in North Cascades National Park. With 1,630 species documented, experts estimate adding non-vascular plants and fungi could more than double

5809-470: Is lessened. This is caused by the loss of snow at the fence that would have been deposited and the pickup of the snow that is already there by the wind, which was depleted of snow at the fence. When there is a sufficient density of trees , they can greatly reduce the strength of avalanches. They hold snow in place and when there is an avalanche, the impact of the snow against the trees slows it down. Trees can either be planted or they can be conserved, such as in

5966-504: Is motivated by the observed difference in the causes of avalanche accidents in the two settings. In the recreational setting most accidents are caused by the people involved in the avalanche. In a 1996 study, Jamieson et al. (pages 7–20) found that 83% of all avalanches in the recreational setting were caused by those who were involved in the accident . In contrast, all the accidents in the residential, industrial, and transportation settings were due to spontaneous natural avalanches. Because of

6123-674: Is only 6 mi (9.7 km) long yet contains 21 peaks over 7,500 ft (2,300 m). North of the Picket Range and near the border with Canada lie Mount Redoubt (8,969 ft (2,734 m)), Mount Spickard (8,979 ft (2,737 m)) and the spires of the Mox Peaks (8,630 ft (2,630 m)). Isolated and dominating the northwestern reaches of the park lies the oft photographed Mount Shuksan (9,131 ft (2,783 m)), which towers more than 8,400 ft (2,600 m) above Baker Lake only 6 mi (9.7 km) to

6280-489: Is part of the area's economy and tourism. In 2008 an Environmental Impact Statement was produced that examined whether these lakes should continue to be stocked, and if so, what the impact would be on native species such as salamanders and other aquatic life. The North Cascades National Park Service Complex Fish Stocking Act, signed in 2014, directs the NPS to allow stocking of non-reproducing fish in no more than 42 lakes, making it

6437-402: Is sufficiently unsettled and cold enough for precipitated snow to accumulate into a seasonal snowpack. Continentality , through its potentiating influence on the meteorological extremes experienced by snowpacks, is an important factor in the evolution of instabilities, and consequential occurrence of avalanches faster stabilization of the snowpack after storm cycles. The evolution of the snowpack

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6594-689: The Cascade Range during the summer months. During the summer, an off-road bus service operated by the NPS carries weary hikers to the town from the Pacific Crest Trail . Visitors to Lake Chelan NRA can get general information about the area at the Golden West Visitor Center located near the ferry landing. The Buckner Homestead Historic District , Purple Point-Stehekin Ranger Station House , and

6751-527: The Haidas , who lived to the north. They erected large houses or lodges that could house multiple families, each with their own partitioned area and entrance. The lodges were 100 feet (30 m) in length and 20 to 40 ft (6.1 to 12.2 m) in width, and the roofs were shed-styles , with a single pitch; structures built by other Puget Sound tribes usually had gable roofs with more than one pitch. The Skagits were generally lowlanders, who only ventured into

6908-694: The Rogers Pass avalanche in British Columbia , Canada. During World War I , an estimated 40,000 to 80,000 soldiers died as a result of avalanches during the mountain campaign in the Alps at the Austrian-Italian front, many of which were caused by artillery fire. Some 10,000 men, from both sides, died in avalanches in December 1916. In the northern hemisphere winter of 1950–1951 approximately 649 avalanches were recorded in

7065-502: The angle of repose , depends on a variety of factors, such as crystal form and moisture content. Some forms of drier and colder snow will only stick to shallower slopes, while wet and warm snow can bond to very steep surfaces. In coastal mountains, such as the Cordillera del Paine region of Patagonia , deep snowpacks collect on vertical and even overhanging rock faces. The slope angle that can allow moving snow to accelerate depends on

7222-496: The avalanche dam on Mount Stephen in Kicking Horse Pass , have been constructed to protect people and property by redirecting the flow of avalanches. Deep debris deposits from avalanches will collect in catchments at the terminus of a run out, such as gullies and river beds. Slopes flatter than 25 degrees or steeper than 60 degrees typically have a lower incidence of avalanches. Human-triggered avalanches have

7379-410: The beaver , hoary marmot and pika are also present. Ten species of bats have been documented. The grey wolf is listed as an endangered species , while the grizzly bear is listed as threatened . North Cascade National Park has management plans in place to return grizzly bears to the park but not wolves, as the latter is seen as likely to reestablish themselves naturally over time. The park

7536-453: The contiguous United States , the headwaters of numerous waterways, and vast forests with the highest degree of flora biodiversity of any American national park. The region was first settled by Paleo-Indian Native Americans ; by the time European American explorers arrived, it was inhabited by Skagit tribes . By the early 19th century, the region was visited by fur trappers and several British and American companies vied for control over

7693-402: The diffuse knapweed and reed canary grass . True grass species number nearly 150 in the park; half of those are considered exotic and nonnative to the ecosystem. Whitebark pine is native to the park and grows at elevations over 5,000 ft (1,500 m) in the drier eastern region of the park. Whitebark pine is a stabilizing species for other species of high altitude flora and provides

7850-606: The fur trade . After the Canada–United States border was set at the 49th parallel in 1846, explorers came to chart potential routes through the mountains for roads and railroads. Limited mining and logging occurred from the late 19th century to the early 20th century. The first significant human impact in the region occurred in the 1920s when several dams were built in the Skagit River valley to generate hydroelectric power. Environmentalists then campaigned to preserve

8007-500: The largemouth bass and longnose dace . Seven species of reptiles and about a dozen species of amphibians have been documented. Reptiles such as the northern alligator lizard and the common garter snake and amphibians such as the western toad , Pacific giant salamander and rough-skinned newt reside in the park. More than 500 species of insects have been recorded, including at least two dozen species of butterflies. Around 250 species of aquatic invertebrates can be found in

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8164-473: The pacific silver fir tree near State Route 20 at Rainy Pass. Also at this elevation, the western hemlock is replaced by the mountain hemlock as a dominant species. At elevations between 4,000 and 7,000 ft (1,200 and 2,100 m) in the subalpine zone, the forest gives way to meadows dominated by grasses and flowering plants and shrubs. Above 7,000 ft (2,100 m) lies the alpine zone where few plant species survive aside from some sparse grasses,

8321-461: The sooty grouse . The peregrine falcon is the only species found in the park that is federally designated as an endangered species, while the marbled murrelet and northern spotted owl are listed as threatened. There are at least 28 species of fish documented, including all five species of Pacific salmon: pink , chinook (king), sockeye , coho and chum . Various trout species including rainbow , lake and brook trout can be found as can

8478-589: The Department of Agriculture allowed commercial enterprises to log the forest with a permit, most of the timber taken from the region was used only locally for the construction of cabins and similar small-scale enterprises. Logging expanded when the Skagit River Hydroelectric Project was commenced by the public utility Seattle City Light in the 1920s. Almost 12,000 acres (4,900 ha) of timber would have been left underwater by

8635-671: The Happy Creek Forest Walk off State Route 20, the Shadows of the Sentinels at Baker Lake, Thunder Creek Trail at Diablo Lake and the Horseshoe Bend Trail from State Route 542 . In openings in the forest canopy, red alder and bigleaf maple can be found but throughout this dense forest, ferns, shrubs and mosses abound. Between 2,000 and 5,500 ft (610 and 1,680 m) the forest is dominated by

8792-509: The Khumbu Icefall), triggering a movement of broken ice chunks. The resulting movement is more analogous to a rockfall or a landslide than a snow avalanche. They are typically very difficult to predict and almost impossible to mitigate. As an avalanche moves down a slope it follows a certain pathway that is dependent on the slope's degree of steepness and the volume of snow/ice involved in the mass movement . The origin of an avalanche

8949-551: The Mazamas Alpine Club lobbied for a bill to designate "Mount Baker National Park". The proposals failed to gain approval from the US Congress and were shelved for decades. Not all locals supported the idea of a national park, as they felt that such a designation would damage the economics of the region. The Forest Service was also not in favor of park designation, as they would have to relinquish control over

9106-619: The National Park Service has conducted rigorous studies on four park glaciers: Noisy Creek , Silver , North Klawatti and Sandalee Glaciers . The National Park Service research indicated that these four glaciers experienced rapid decrease in volumes between 1993 and 2011. In 1998, a National Park Service and Portland State University aerial photographic inventory showed a 13 percent loss in park-wide glacial volume since Austin Post's inventory in 1971. The NPS stated that in

9263-608: The North Cascade glaciers brought about some of the earliest series of scientific studies regarding glaciology in the United States. Beginning in 1955, the University of Washington sponsored Richard C. Hubley to undertake annual aerial photography expeditions designed to capture images of the glaciers and to show any alterations that might be occurring. In 1960, Austin Post expanded the aerial coverage to include other regions and he also used ground-based imagery to augment

9420-479: The North Cascade region was designated as a Forest Reserve in 1897, activists argued the region should be afforded the greater protection accorded from a National Park designation. Washingtonians submitted a petition in 1892 to establish a national park to the north of Lake Chelan , as many who had visited the region believed it to have scenery "greater than Switzerland's". Further efforts took place in 1906, and again between 1916 and 1921, when artist Julian Itter and

9577-518: The North Cascades during the summer months, and structures in the mountains were more modest, consisting mostly of temporary buildings erected with poles and covered with branches. The Skagits erected totem poles and participated in potlatch ceremonies, similar to the Haidas, but with less complexity and extravagance. By 1910, only about 56 Skagits remained in the region, but their numbers have since rebounded to several hundred. Inland and residing to

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9734-491: The North Cascades region, which included the national park and surrounding national forests. In 1997, the North Cascades region was added to the National Grizzly Bear Recovery Plan; by 2017, the environmental impact statement for grizzly bear restoration was still in the public comment stage. Various action plans had been proposed to reestablish a self-sustaining population of 200 grizzlies in

9891-451: The North Cascades saw no further explorations until the 1850s. In 1853, US Army Captain George B. McClellan led a party that explored the area for potential locations for the construction of a railroad through the region. McClellan determined the mountains were too numerous and precipitous, and that any railway would have to be constructed well to the south. American and British disputes in

10048-573: The Ross Lake NRA and outside of the national park boundaries, but some of the creeks and streams that supply it originate within the national park; the Baker River is the largest of these tributaries. The Skagit River is the largest river that flows into Puget Sound to the west, and the dams located in Ross Lake National Recreation Area and impounding other lakes adjacent to the park supply nearly 90 percent of

10205-517: The SAMOS-AT avalanche simulation software and the RAMMS software. Preventative measures are employed in areas where avalanches pose a significant threat to people, such as ski resorts , mountain towns, roads, and railways. There are several ways to prevent avalanches and lessen their power and develop preventative measures to reduce the likelihood and size of avalanches by disrupting the structure of

10362-517: The United States and Canada; the latter manages adjoining Chilliwack Lake and Skagit Valley Provincial Park . The entire eastern and southern boundary of the north district is bordered by Ross Lake NRA. The western side of the north district is bordered by Mount Baker-Snoqualmie National Forest , within which lies the Mount Baker and Noisy-Diobsud Wildernesses , both of which border the park. Mount Baker-Snoqualmie National Forest also borders

10519-411: The United States. In 2001 it was reported that globally an average of 150 people die each year from avalanches. Three of the deadliest recorded avalanches have killed over a thousand people each. Doug Fesler and Jill Fredston developed a conceptual model of the three primary elements of avalanches: terrain, weather, and snowpack. Terrain describes the places where avalanches occur, weather describes

10676-408: The ambient air temperature can be much colder. When a temperature gradient greater than 10 °C change per vertical meter of snow is sustained for more than a day, angular crystals called depth hoar or facets begin forming in the snowpack because of rapid moisture transport along the temperature gradient. These angular crystals, which bond poorly to one another and the surrounding snow, often become

10833-426: The avalanche's path to slow it down. Finally, along transportation corridors, large shelters, called snow sheds , can be built directly in the slide path of an avalanche to protect traffic from avalanches. Warning systems can detect avalanches which develop slowly, such as ice avalanches caused by icefalls from glaciers. Interferometric radars, high-resolution cameras, or motion sensors can monitor instable areas over

10990-400: The banks of the Skagit River in search of gold. In the 1870s, placer mining also commenced along Ruby Creek , and hundreds of miners came to the region even though it was difficult to access. Most mining activity along Ruby Creek had ended by the 1880s, but was soon replaced by hard rock mining for silver and other minerals. This second period of mining lasted from the 1890s to the 1940s, but

11147-603: The border should be. The Oregon boundary dispute between Britain and the United States eventually led to the Oregon Treaty of 1846, and the 49th parallel forms both the current international border as well as the northern limit of the current park. During the late 1850s, members of the US North West Boundary Commission explored the border region, attempting to identify which mountains, rivers and lakes belonged to which country. One party of

11304-438: The budget is for staffing, with 83 percent covering the cost of 81 permanent employees, not all of whom are employed year-round, and the nearly 250 seasonal and term employees who work primarily in the summer months. In 2017, the fiscal year budget was approximately 7.5 million dollars, and budgets have been stagnant overall for all National Park Service sites for many years. Although there are some gravel roads open to

11461-401: The building of a ski resort, to reduce the strength of avalanches. In turn, socio-environmental changes can influence the occurrence of damaging avalanches: some studies linking changes in land-use/land-cover patterns and the evolution of snow avalanche damage in mid latitude mountains show the importance of the role played by vegetation cover, that is at the root of the increase of damage when

11618-432: The bulk of the avalanche. Driving an avalanche is the component of the avalanche's weight parallel to the slope; as the avalanche progresses any unstable snow in its path will tend to become incorporated, so increasing the overall weight. This force will increase as the steepness of the slope increases, and diminish as the slope flattens. Resisting this are a number of components that are thought to interact with each other:

11775-423: The commission was led by explorer Henry Custer, and they explored the northern district of the park, publishing their report in the 1860s. Custer's party crossed Whatcom Pass in 1858, and were the first whites to see Challenger Glacier and Hozomeen Mountain. Impressed with the scenic grandeur of the region, Custer stated, "must be seen, it cannot be described". In 1882, US Army Lieutenant Henry Hubbard Pierce led

11932-544: The completion of the Ross Dam . A contract to extract the timber was awarded in 1945 and the project was completed in 1958. None of the dams or areas that were extensively logged are within the current boundaries of the national park, but they are in the adjoining Ross Lake National Recreation Area . The establishment of Yellowstone National Park in 1872, and Yosemite National Park in 1890, led preservationists to argue for similar protections for other areas. Even before

12089-505: The contiguous US, rising between 4,000 and 6,000 ft (1,200 and 1,800 m) above their bases. The park is home to over 300 glaciers as well as 300 lakes, and contains the headwaters for some streams that flow into the Skagit River, as well as the Stehekin and Nooksack Rivers . The ruggedness of the terrain was an obstacle to human encroachment and consequently, the park is almost entirely wilderness. North Cascades National Park

12246-409: The depths, crystal forms, and layering of the seasonal snowpack. Slab avalanches are formed frequently in snow that has been deposited, or redeposited by wind. They have the characteristic appearance of a block (slab) of snow cut out from its surroundings by fractures. Elements of slab avalanches include a crown fracture at the top of the start zone, flank fractures on the sides of the start zones, and

12403-635: The difference in the causes of avalanche accidents, and the activities pursued in the two settings, avalanche and disaster management professionals have developed two related preparedness, rescue, and recovery strategies for each of the settings. Two avalanches occurred in March 1910 in the Cascade and Selkirk Mountain ranges; on 1 March the Wellington avalanche killed 96 in Washington state , United States. Three days later 62 railroad workers were killed in

12560-532: The early 20th century, notably the work of Professor Lagotala in preparation for the 1924 Winter Olympics in Chamonix . His method was developed by A. Voellmy and popularised following the publication in 1955 of his Ueber die Zerstoerungskraft von Lawinen (On the Destructive Force of Avalanches). Voellmy used a simple empirical formula, treating an avalanche as a sliding block of snow moving with

12717-551: The east. Chelan is located at the southeastern end of Lake Chelan where access to the park from Stehekin serves eastern Washington communities. The closest international airport is Seattle-Tacoma International Airport (Sea-Tac), which is 120 mi (190 km) from North Cascades Visitor Center and 190 mi (310 km) from Chelan. In Chelan, the Lady of the Lake is a passenger-only ferry that transports visitors to Stehekin, and

12874-695: The electricity used in Seattle. Other important rivers that originate in the park include the Chilliwack , Nooksack and the Stehekin rivers. With approximately 312 glaciers, North Cascades National Park has the most glaciers of any US park outside Alaska, and a third of all the glaciers in the lower 48 states. Counting a few glaciers in the adjoining National Recreation Areas, the North Cascades National Park Complex glaciers covered an expanse totaling 27,000 acres (110 km ) as of 2009. Boston Glacier , on

13031-496: The fabrication of implements, was mined from near Hozomeen Mountain , just east of the park border, for the last 8,400 years. Tools such as microblades made from Hozomeen chert are part of the archaeological record throughout the Skagit River Valley, west of the park and in regions to the east. Prehistoric micro blades 9,600 years old have been discovered at Cascade Pass , a mountain pass that connects

13188-534: The fact that each avalanche is unique depending on the stability of the snowpack that it was derived from as well as the environmental or human influences that triggered the mass movement. People caught in avalanches can die from suffocation , trauma, or hypothermia . From "1950–1951 to 2020–2021" there were 1,169 people who died in avalanches in the United States. For the 11-year period ending April 2006, 445 people died in avalanches throughout North America. On average, 28 people die in avalanches every winter in

13345-452: The flow of a wet snow avalanche can plough through soft snow, and can scour boulders, earth, trees, and other vegetation; leaving exposed and often scored ground in the avalanche track. Wet snow avalanches can be initiated from either loose snow releases, or slab releases, and only occur in snowpacks that are water saturated and isothermally equilibrated to the melting point of water. The isothermal characteristic of wet snow avalanches has led to

13502-505: The fossils and magnetism found in the rocks indicates that the terranes composing the North Cascades drifted thousands of miles north until they impacted the North American Plate 90 million years ago. The collision between the rocks caused fracturing and folding as well as uplift and the terranes were further fractured into north or south trending faults. The uplifted rocks mostly eroded away; 40 million years ago

13659-460: The friction between the avalanche and the surface beneath; friction between the air and snow within the fluid; fluid-dynamic drag at the leading edge of the avalanche; shear resistance between the avalanche and the air through which it is passing, and shear resistance between the fragments within the avalanche itself. An avalanche will continue to accelerate until the resistance exceeds the forward force. Attempts to model avalanche behaviour date from

13816-411: The fur trading company. During one season, Ross traded 1,500 beaver pelts. In 1814, Ross became the first known white explorer to explore the valleys and high passes of the North Cascades, but he was less interested in exploration than discovering a route that would easily connect the fur trading posts of interior Washington with Puget Sound to the west. Ross was accompanied by three Indians, one of whom

13973-470: The greatest incidence when the snow's angle of repose is between 35 and 45 degrees; the critical angle, the angle at which human-triggered avalanches are most frequent, is 38 degrees. When the incidence of human triggered avalanches is normalized by the rates of recreational use, however, hazard increases uniformly with slope angle, and no significant difference in hazard for a given exposure direction can be found. The rule of thumb is: A slope that

14130-866: The ground surface beneath the snowpack influences the stability of the snowpack, either being a source of strength or weakness. Avalanches are unlikely to form in very thick forests, but boulders and sparsely distributed vegetation can create weak areas deep within the snowpack through the formation of strong temperature gradients. Full-depth avalanches (avalanches that sweep a slope virtually clean of snow cover) are more common on slopes with smooth ground, such as grass or rock slabs. Generally speaking, avalanches follow drainages down-slope, frequently sharing drainage features with summertime watersheds. At and below tree line , avalanche paths through drainages are well defined by vegetation boundaries called trim lines , which occur where avalanches have removed trees and prevented regrowth of large vegetation. Engineered drainages, such as

14287-401: The heavier basaltic rocks of the ocean floor started to push the lighter granitic rocks that are the core of the mountains upward, a process that continues. Subjected to intense heat, rocks deep underground near the collision zone became recrystallized into granitic rocks, which comprise the backbone of the highest peaks. Continued uplift and erosion and finally the action of glacial ice on

14444-508: The influence of the meteorological conditions that prevail after deposition. For an avalanche to occur, it is necessary that a snowpack have a weak layer (or instability) below a slab of cohesive snow. In practice the formal mechanical and structural factors related to snowpack instability are not directly observable outside of laboratories, thus the more easily observed properties of the snow layers (e.g. penetration resistance, grain size, grain type, temperature) are used as index measurements of

14601-593: The land to the Park Service, which was not uncommon, since many parks being established were originally managed by the Forest Service. In an effort to appease their detractors, the Forest Service designated Primitive Areas which would provide increased protection to some of the most pristine regions they managed. By the mid-1930s, forester Bob Marshall argued that the region should be set aside as wilderness. Rival interests continued to argue over whether

14758-600: The lands should remain under the management of the Forest Service or the National Park Service, but by the 1960s the environmentalist argument advocating for a national park prevailed. President John F. Kennedy directed the Departments of Agriculture and the Interior to fund a joint study into a possible national park in the North Cascades region, which was completed in January 1966 and submitted to Congress. The size of

14915-465: The landscape during the Holocene exposed the rocks visible today. Much harder and more durable than the younger volcanic rocks of the southern Cascades, the North Cascades are consequently more rugged, with steep terrain being the norm due to heavy erosion from water and ice. Continued rising in conjunction with erosion from water and ice has created deep valleys and significant vertical relief that

15072-487: The last 150 years since the end of the Little Ice Age , a period of several centuries in which the earth experienced a cooling phase, glacial ice volumes in the North Cascades have been reduced by 40 percent. This loss of glacial ice has contributed to decreased melt in the summer. In a paper published in 2016, it was reported that since 1959 the Skagit River watershed has seen a 25 percent reduction in

15229-413: The likelihood of an avalanche. Observation and experience has shown that newly fallen snow requires time to bond with the snow layers beneath it, especially if the new snow falls during very cold and dry conditions. If ambient air temperatures are cold enough, shallow snow above or around boulders, plants, and other discontinuities in the slope, weakens from rapid crystal growth that occurs in the presence of

15386-450: The local humidity, water vapour flux, temperature and heat flux. The top of the snowpack is also extensively influenced by incoming radiation and the local air flow. One of the aims of avalanche research is to develop and validate computer models that can describe the evolution of the seasonal snowpack over time. A complicating factor is the complex interaction of terrain and weather, which causes significant spatial and temporal variability of

15543-452: The lower 48 states. More than 200 species of birds that pass through or use the park as a breeding ground have been recorded. These bird species include both golden and bald eagle as well as northern spotted owl , harlequin duck , Clark's nutcracker , trumpeter swan and seasonal appearances of western tanager , Cassin's vireo , pine grosbeak , woodpeckers such as the pileated woodpecker and primarily ground-dwelling birds such as

15700-526: The mechanical properties of the snow (e.g. tensile strength , friction coefficients, shear strength , and ductile strength ). This results in two principal sources of uncertainty in determining snowpack stability based on snow structure: First, both the factors influencing snow stability and the specific characteristics of the snowpack vary widely within small areas and time scales, resulting in significant difficulty extrapolating point observations of snow layers across different scales of space and time. Second,

15857-421: The meteorological conditions that create the snowpack, and snowpack describes the structural characteristics of snow that make avalanche formation possible. Avalanche formation requires a slope shallow enough for snow to accumulate but steep enough for the snow to accelerate once set in motion by the combination of mechanical failure (of the snowpack) and gravity. The angle of the slope that can hold snow, called

16014-500: The military in 1883 and 1887 also determined that the mountains were virtually impenetrable. Explorers continued to seek out routes for wagon roads and railways and by the end of the 19th century, much of the park had been explored, but it was not until 1972 that the North Cascades Highway bisected the mountains. Mineral prospectors entered the North Cascades region, and by the 1850s were doing placer mining along

16171-480: The moderating influence of the Pacific Ocean. Inland tribes rarely erected totem poles or participated in potlatch ceremonies. By the beginning of the 20th century, inland tribes, like their coastal neighbors, had experienced population decline from their first contact with white explorers a hundred years earlier, mostly due to smallpox and other diseases. The first white explorer to enter the North Cascades

16328-559: The national park was subject to debate locally and in Congress, as well as its effect on the local logging industry. The North Cascades National Park Act designated the region as a national park on October 2, 1968, and the National Park Service commenced direct management on January 1, 1969. The North Cascades National Park Act also designated Ross Lake and Lake Chelan National Recreation Areas . Redwood National Park in California

16485-414: The new snow has insufficient time to bond to underlying snow layers. Rain has a similar effect. In the short term, rain causes instability because, like a heavy snowfall, it imposes an additional load on the snowpack and once rainwater seeps down through the snow, acts as a lubricant, reducing the natural friction between snow layers that holds the snowpack together. Most avalanches happen during or soon after

16642-427: The night and of unstable surface snow during the day. Slopes in the lee of a ridge or of another wind obstacle accumulate more snow and are more likely to include pockets of deep snow, wind slabs , and cornices , all of which, when disturbed, may result in avalanche formation. Conversely, the snowpack on a windward slope is often much shallower than on a lee slope. Avalanches and avalanche paths share common elements:

16799-618: The north and east of the Skagit tribe, the Nlaka'pamux (also known as the "Thompson Indians", named after explorer David Thompson ), Chelan , Okanogan and Wenatchi (Wenatchee) tribes lived partly or year-round in the eastern sections of the North Cascades. The Skagits and Nlaka'pamux often had disputes, and raided one another's camps in search of slaves or to exact retribution. Like the coastal-based Skagits, inland tribes also constructed long lodges which were occupied by numerous families, though

16956-539: The north slope of Boston Peak, is the largest glacier in the park, measured in 1971 to have an area of 1,730 acres (7.0 km ). Other glaciers that were measured in 1971 to be larger than 2 square kilometres (0.77 sq mi) include East Nooksack and Sulphide Glaciers on Mount Shuksan , McAllister and Inspiration Glaciers on Eldorado Peak, Redoubt Glacier on Mount Redoubt , Neve Glacier on Snowfield Peak , and Challenger Glacier on Mount Challenger. The dense concentration and relative ease of access to

17113-675: The number of known plant species. The park contains an estimated 236,000 acres (960 km ) of old-growth forests . As little of the park was previously logged, significant stands of old growth forest can be found in the valleys and lower slopes up to the timberline at 7,000 ft (2,100 m). From the lowest valley floors to about 2,000 ft (610 m), virgin stands of western hemlock , red cedar and Douglas fir are common. These species are heavily dependent on deep soils, and red cedars 1,000 years old and over 200 ft (61 m) tall can be found on Big Beaver Creek. These lowest elevation forests can be accessed by trails, such as

17270-483: The occasional shrub and lichens. A warming climate has led to an altitude adjustment for many flora species, with the timberline reaching 415 ft (126 m) further up the mountain slopes since the 1960s. The biodiversity of the area is threatened by climate change and invasive exotic plant species. These plants have spread across the park through the inadvertent redistribution from human activities, attaching themselves to cars and hikers. Invasive plants include

17427-612: The one-room Stehekin School are in the Lake Chelan NRA. They are all listed on the National Register of Historic Places . This Chelan County, Washington state location article is a stub . You can help Misplaced Pages by expanding it . This National Park Service related article is a stub . You can help Misplaced Pages by expanding it . North Cascades National Park North Cascades National Park

17584-491: The only national park to continue to stock non-native fish in park lakes. The prior decision not to continue to stock the lakes with fish was part of a larger debate about what "natural" means in reference to national parks. Hundreds of creeks and streams and several rivers originate within the park. The streams at higher elevation are often directly supplied by meltwater from glaciers, and they carry finely ground rock particles commonly referred to as glacial flour . Turning

17741-578: The park are from the more recent Mesozoic, the oldest rocks are 400 million years old, dating from the Devonian . A complex assemblage of various rock formations have repeatedly been eroded, reburied, subjected to fracturing and heat, creating a geological puzzle that is one of the most complicated and least understood geological records in North America. These forces are ongoing and the region continues to see uplift and faulting. Evidence from

17898-412: The park has few structures, roads or other improvements. Visitors wishing to drive to a campground must do so in the adjacent national forests or national recreation areas. Camping inside the park requires hiking in by trail, horseback or boat, and camping is regulated by a permit system to ensure the wilderness is not over-exploited. Mountaineering is popular in the park and only unobtrusive clean climbing

18055-527: The park. When white explorers first entered the area in the late 18th century, an estimated thousand Native American Skagits lived in what is now North Cascades National Park as well as the surrounding area. Residing mainly to the west of the park near Puget Sound , the Skagits lived in settlements, culling their needs from the waterways and traveling by canoe. Skagits formed a loose confederation of tribes that united if threatened by outside tribes such as

18212-491: The park. The mandate of the National Park Service is to "preserve and protect natural and cultural resources". In keeping with this mandate, hunting is illegal in the park, as is mining, logging, oil and gas extraction, and removal of natural or cultural resources. In 2016, North Cascades National Park recorded 28,646 visitors, while adjoining Ross Lake National Recreation Area reported 905,418 visitors and Lake Chelan National Recreation Area had 45,514 visitors. Peak visitation

18369-502: The park. All backcountry access requires a permit, and most are obtained at the Wilderness Information Center near Marblemount. Full accessibility for all is not available in the park, but the adjacent National Recreation Areas have a few trails, and all visitor centers, campgrounds and restrooms are fully accessible. The nearest large town on the west side of the park is Sedro-Woolley, and Winthrop lies to

18526-565: The parks waterways. Avalanche An avalanche is a rapid flow of snow down a slope , such as a hill or mountain. Avalanches can be triggered spontaneously, by factors such as increased precipitation or snowpack weakening, or by external means such as humans, other animals, and earthquakes . Primarily composed of flowing snow and air, large avalanches have the capability to capture and move ice, rocks, and trees. Avalanches occur in two general forms, or combinations thereof: slab avalanches made of tightly packed snow, triggered by

18683-407: The path. The frequency with which avalanches form in a given area is known as the return period . The start zone of an avalanche must be steep enough to allow snow to accelerate once set in motion, additionally convex slopes are less stable than concave slopes because of the disparity between the tensile strength of snow layers and their compressive strength . The composition and structure of

18840-442: The plant and animal species native to the park region are still found there, though climate change and pollutants from industrialized regions to the west pose risks to the environment. The park has one of the earliest and longest lasting research programs dedicated to studying climate change, primarily through examining the effects of glacial retreat . North Cascades National Park is almost entirely protected as wilderness , and so

18997-414: The prevention of development in these areas. To mitigate the effect of avalanches the construction of artificial barriers can be very effective in reducing avalanche damage. There are several types: One kind of barrier ( snow net ) uses a net strung between poles that are anchored by guy wires in addition to their foundations. These barriers are similar to those used for rockslides . Another type of barrier

19154-550: The protective forest is deforested (because of demographic growth, intensive grazing and industrial or legal causes), and at the root of the decrease of damage because of the transformation of a traditional land-management system based on overexploitation into a system based on land marginalization and reforestation, something that has happened mainly since the mid-20th century in mountain environments of developed countries. In many areas, regular avalanche tracks can be identified and precautions can be taken to minimize damage, such as

19311-870: The public that enter the park, such as the Cascade River Road beginning at Marblemount , and the Thornton Lakes Road near Newhalem , most automobile traffic travels on State Route 20, which passes through the Ross Lake National Recreation Area. The visitor center at Newhalem on the North Cascades Highway is open in the summer. Some of the best views of Mount Shuksan are from the Heather Meadows Visitor Center in Mount Baker-Snoqualmie National Forest well outside of

19468-804: The recent work was carried out as part of the SATSIE (Avalanche Studies and Model Validation in Europe) research project supported by the European Commission which produced the leading-edge MN2L model, now in use with the Service Restauration des Terrains en Montagne (Mountain Rescue Service) in France, and D2FRAM (Dynamical Two-Flow-Regime Avalanche Model), which was still undergoing validation as of 2007. Other known models are

19625-554: The region became a national park, some privately owned mining inholdings remained. One such inholding, the Thunder Creek mine, was still privately owned as of 1997. Unlike in many other regions of the Pacific Northwest, logging had little impact on the future park. The ruggedness of the terrain and the existence of more economically viable timber resources that were closer to transportation routes largely dissuaded

19782-749: The region centered on the fur trade, and the Treaty of 1818 allowed for joint administration of Oregon Country , as it was referred to in the United States ;– the British Empire referred to the region as the Columbia District . The treaty set the international border at the 49th parallel , but this was disputed west of the Rocky Mountains , since the rival fur trading outfits had their own ideas about where

19939-453: The region. Wolverines are one of the rarest and most elusive mammals in North America. They are seldom sighted in the park, both due to the limited numbers of the species and the habitats they prefer, which are snowy high-altitude regions far removed from human encroachment. Approximately nine wolverines were captured in the national forest east of the park and fitted with transmitters that were tracked by Argos satellite telemetry. Four of

20096-409: The relationship between readily observable snowpack characteristics and the snowpack's critical mechanical properties has not been completely developed. While the deterministic relationship between snowpack characteristics and snowpack stability is still a matter of ongoing scientific study, there is a growing empirical understanding of the snow composition and deposition characteristics that influence

20253-416: The remaining wilderness, culminating on October 2, 1968, with the designation of North Cascades National Park. Heavy snows and a high risk of avalanches due to the steep terrain, especially on the western slopes, severely limit visitation in the winter. Most access to the park is from State Route 20 , which follows the Skagit River, though even this road is closed for months at a time in the winter. Most of

20410-478: The research. In 1971, based on the photographs and other data collected since 1955, Post and others wrote a report that documented the number and scale of glaciers in the North Cascades. At the time of Austin Post's inventory, their study concluded that some North Cascades glaciers had experienced a period of minor growth or equilibrium in the mid-20th century, after undergoing decades of retreat. The study concluded that annual glacial melt due to seasonal variations has

20567-642: The route followed by members of the Lewis and Clark Expedition of 1804–1806, and also north of Fort Vancouver , on the Columbia River . Fort Okanogan was later owned by the North West Company , and then the Hudson's Bay Company , both of which were British-owned. Both Native American and white trappers conducted fur transactions at the trading post, which was staffed by representatives of

20724-458: The secondary term of isothermal slides found in the literature (for example in Daffern, 1999, p. 93). At temperate latitudes wet snow avalanches are frequently associated with climatic avalanche cycles at the end of the winter season, when there is significant daytime warming. An ice avalanche occurs when a large piece of ice, such as from a serac or calving glacier, falls onto ice (such as

20881-416: The slab may not have time to adjust to the new load. Even on a clear day, wind can quickly load a slope with snow by blowing snow from one place to another. Top-loading occurs when wind deposits snow from the top of a slope; cross-loading occurs when wind deposits snow parallel to the slope. When a wind blows over the top of a mountain, the leeward, or downwind, side of the mountain experiences top-loading, from

21038-429: The snowpack can hide below well-consolidated surface layers. Uncertainty associated with the empirical understanding of the factors influencing snow stability leads most professional avalanche workers to recommend conservative use of avalanche terrain relative to current snowpack instability. Avalanches only occur in a standing snowpack. Typically winter seasons at high latitudes, high altitudes, or both have weather that

21195-423: The snowpack, and the heat stored in the snow is re-radiated into the atmosphere. When a slab avalanche forms, the slab disintegrates into increasingly smaller fragments as the snow travels downhill. If the fragments become small enough the outer layer of the avalanche, called a saltation layer, takes on the characteristics of a fluid . When sufficiently fine particles are present they can become airborne and, given

21352-460: The snowpack, such as melting due to solar radiation, is the second-largest cause of natural avalanches. Other natural causes include rain, earthquakes, rockfall, and icefall. Artificial triggers of avalanches include skiers, snowmobiles, and controlled explosive work. Contrary to popular belief, avalanches are not triggered by loud sound; the pressure from sound is orders of magnitude too small to trigger an avalanche. Avalanche initiation can start at

21509-479: The snowpack, while passive measures reinforce and stabilize the snowpack in situ . The simplest active measure is repeatedly traveling on a snowpack as snow accumulates; this can be by means of boot-packing, ski-cutting, or machine grooming . Explosives are used extensively to prevent avalanches, by triggering smaller avalanches that break down instabilities in the snowpack, and removing overburden that can result in larger avalanches. Explosive charges are delivered by

21666-402: The snowpack; conversely, very cold, windy, or hot weather will weaken the snowpack. At temperatures close to the freezing point of water, or during times of moderate solar radiation, a gentle freeze-thaw cycle will take place. The melting and refreezing of water in the snow strengthens the snowpack during the freezing phase and weakens it during the thawing phase. A rapid rise in temperature, to

21823-448: The south. More than 500 lakes and ponds are located within North Cascades National Park. Many of these are devoid of fish, not uncommon in steep terrain where fish may not be able to access high altitude waterways. Around 240 of these lakes exist in the higher elevations and stocking of some of these lakes with fish has been ongoing since the late 19th century. Fishing in these lakes, which, without fish stocking, do not have native fish,

21980-430: The southeastern park boundary. North Cascades National Park has nearly 9,000 feet (2,700 m) of vertical relief, with the park's highest point atop Goode Mountain , and the western valleys situated at only around 400 ft (120 m) above mean sea level , the park has a highly varied ecosystem, including eight life zones . Erosion from water and glacial ice have created some of the steepest mountain ranges in

22137-476: The southern border of the south unit of the park. In addition to the two national recreation areas , other protected lands including several national forests and wilderness areas , as well as Canadian provincial parks in British Columbia , nearly surround the park. North Cascades National Park features the rugged mountain peaks of the North Cascades Range , the most expansive glacial system in

22294-401: The strength. The load is straightforward; it is the weight of the snow. However, the strength of the snowpack is much more difficult to determine and is extremely heterogeneous. It varies in detail with properties of the snow grains, size, density, morphology, temperature, water content; and the properties of the bonds between the grains. These properties may all metamorphose in time according to

22451-540: The style of construction was slightly different as the lodges did not have partitions separating one family from another, and were frame constructed and covered with reed mats rather than from cedar planking. One Wenatchee tribal lodge was described by Thompson as being 240 ft (73 m) long. Inland tribes were more likely to travel on foot or horseback than by canoe since the inland regions were less densely forested. Inland tribes also had less bountiful fisheries and greater weather extremes due to being further away from

22608-430: The summertime streamflow. Geographical features in the area can be found in this clickable map: Eight distinctive life zones support thousands of different plant and animal species in the North Cascades National Park ecosystem . With an elevation gain of nearly 9,000 ft (2,700 m), the park has one of the largest ranges of biodiversity found in any US national park. The flora in North Cascades National Park

22765-572: The timber industry from logging in the area. In 1897 the Washington Forest Reserve was set aside, preserving the forestland that would later become the park. By 1905, the management of the reserve was transferred from the Department of the Interior to the Department of Agriculture . The Forest Service was subsequently created to administer these forest reserves nationwide, which were redesignated as National Forests. Though

22922-421: The top to the bottom of that lee slope. When the wind blows across a ridge that leads up the mountain, the leeward side of the ridge is subject to cross-loading. Cross-loaded wind-slabs are usually difficult to identify visually. Snowstorms and rainstorms are important contributors to avalanche danger. Heavy snowfall will cause instability in the existing snowpack, both because of the additional weight and because

23079-405: The trailheads hikers can use to access the southern end of the park. North Cascades National Park is located in portions of Whatcom , Skagit , and Chelan counties in the U.S. state of Washington. Bisected by Ross Lake National Recreation Area (NRA), the park consists of two districts; the northern and southern. The northern boundary of the north district is also the international border between

23236-449: The warmer months. In addition to industrially manufactured barriers, landscaped barriers, called avalanche dams stop or deflect avalanches with their weight and strength. These barriers are made out of concrete, rocks, or earth. They are usually placed right above the structure, road, or railway that they are trying to protect, although they can also be used to channel avalanches into other barriers. Occasionally, earth mounds are placed in

23393-420: The water a turquoise hue at times, this finely ground powder remains suspended in lakes the creeks flow into, also causing some of them to appear turquoise. Thunder Creek is particularly well known for this attribute, as it is supplied melt water from dozens of glaciers and transports the suspended particles into Diablo Lake . The Skagit River divides the park into the north and south districts; it lies within

23550-478: The western lowlands to the interior regions of the park and the Stehekin River Valley. The microblades are part of an archaeological assemblage that includes five distinct cultural periods, indicating that people were traveling into the mountains nearly 10,000 years ago. As well as the archaeological excavation at Cascade Pass, there are another 260 prehistoric sites that have been identified in

23707-553: The wolverines frequented the southern sections of North Cascades National Park, and of those, two spent the majority of their time there; researchers were unable to determine if these study animals had reproduced in the park. A warming climate may impact any wolverine recovery efforts implemented due to the loss of snow cover this species needs to reproduce. Research indicates that wolverines den in deep snow at least 5 ft (1.5 m) deep that lasts well into May, and as climate warms, these regions are becoming less common, especially in

23864-485: The year. In mountainous areas, avalanches are among the most serious natural hazards to life and property, so great efforts are made in avalanche control . There are many classification systems for the different forms of avalanches. Avalanches can be described by their size, destructive potential, initiation mechanism, composition, and dynamics . Most avalanches occur spontaneously during storms under increased load due to snowfall and/or erosion . Metamorphic changes in

24021-442: Was a guide who led the party to a high pass in the North Cascades. Ross and the guide may have traveled as far west as the Skagit River, but failed to get to Puget Sound. Fur trading slowed considerably as demand for furs decreased in the 1840s, but a few residents continued to augment their income by trapping for furs in the area until 1968, when the park was established, rendering the activity illegal. Aside from isolated trappers,

24178-566: Was also signed into existence on the same day as the North Cascades. By 1988, much of Bob Marshall's original plan to set aside the future park as wilderness was achieved when almost all of North Cascades National Park was designated as the Stephen Mather Wilderness . North Cascades National Park is managed by the National Park Service, and the park headquarters is in Sedro-Woolley, Washington . The park consists of

24335-517: Was most likely a Scotsman named Alexander Ross , who was in the employ of the American-owned Pacific Fur Company . To the southeast of the modern park boundary, Ross and other members of the company constructed Fort Okanogan in 1811, as a base from which to operate during the early period of the Pacific Northwest fur trade. Fort Okanogan was the first American settlement in present-day Washington State, well north of

24492-489: Was named after the North Cascades mountains, which are a subsection of the Cascade Range that extends from northern California into British Columbia. The North Cascades are the northernmost section of the range and unlike their southern counterparts that consist of Tertiary to Holocene volcanic rocks, the North Cascades are composed primarily of Mesozoic crystalline and metamorphic rocks . Though most rocks in

24649-433: Was only marginally more lucrative. Miners were hampered by short working seasons, difficult terrain, low quantities of ore and a lack of financial investment. Miners built some of the first trails and roads into portions of the backcountry, some of which involved intricate engineering, including bridges over the numerous streams and dynamiting rock ledges above steep gorges during trail construction. One mining company built

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