60-650: The Conejo Grade is a 7% grade incline on a section of US 101 (the Ventura Freeway ). Also known as the Camarillo Grade , it links Thousand Oaks and cities of the Conejo Valley , with Camarillo and the cities on the Oxnard Plain . With a summit elevation of 841.1 feet (256.4 m), California Highway Patrol inspection stations for trucks are situated on both sides of the highway at
120-558: A "strange, dust-laden windstorm" arrived in the night while his troops were marching south through California in January 1847. Various episodes of hot, dry winds have been described over this history as dust storms, hurricane-force winds, and violent north-easters, damaging houses and destroying fruit orchards. Newspaper archives have many photographs of regional damage dating back to the beginnings of news reporting in Los Angeles. When
180-409: A 71 percent grade instead of a 100 percent. But in practice the usual way to calculate slope is to measure the distance along the slope and the vertical rise, and calculate the horizontal run from that, in order to calculate the grade (100% × rise/run) or standard slope (rise/run). When the angle of inclination is small, using the slope length rather than the horizontal displacement (i.e., using
240-569: A full glass of beer at a cocktail lounge. The baby frets. The maid sulks. I rekindle a waning argument with the telephone company, then cut my losses and lie down, given over to whatever is in the air. To live with the Santa Ana is to accept, consciously or unconsciously, a deeply mechanistic view of human behavior. ... [T]he violence and the unpredictability of the Santa Ana affect the entire quality of life in Los Angeles, accentuate its impermanence, its unreliability. The wind shows us how close to
300-416: A pathogenic fungus that causes Coccidioidomycosis ("Valley Fever"). Symptomatic infection (40 percent of cases) usually presents as an influenza-like illness with fever, cough, headaches, rash, and myalgia (muscle pain). Serious complications include severe pneumonia, lung nodules, and disseminated disease, where the fungus spreads throughout the body. The disseminated form of Coccidioidomycosis can devastate
360-415: A physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal . It is a special case of the slope , where zero indicates horizontality . A larger number indicates higher or steeper degree of "tilt". Often slope is calculated as a ratio of "rise" to "run", or as a fraction ("rise over run") in which run is the horizontal distance (not the distance along
420-411: A strong correlation with the highest "regionally averaged" wind speeds. Santa Ana winds often bring the lowest relative humidities of the year to coastal Southern California. These low humidities, combined with the warm, compressionally-heated air mass , plus the high wind speeds, create critical fire weather conditions. The combination of wind, heat, and dryness accompanying the Santa Ana winds turns
480-423: A sudden and surprising transition from the hot, dry Santa Ana conditions to cool, moist, and gray marine weather, as the Santa Ana fog can blow onshore and envelop cities in as quickly as fifteen minutes. However, a true Santa Ana fog is rare, because it requires conditions conducive to rapid re-forming of the marine layer, plus a rapid and strong reversal in wind gradients from off-shore to on-shore winds. More often,
540-517: A trading trail through the pass, and it later served as a trading route for farmers and their wagons down the Conejo Grade to the Hueneme wharf . The grade experienced improvements by the newly established State Highway Department in 1912, when the road measured six miles (9.7 km) long and had 49 curves. Traffic kept increasing and the road was straightened and relocated in 1935. The new road
600-687: A vehicle can ascend while maintaining a particular speed is sometimes termed that vehicle's "gradeability" (or, less often, "grade ability"). The lateral slopes of a highway geometry are sometimes called fills or cuts where these techniques have been used to create them. In the United States, the maximum grade for federally funded highways is specified in a design table based on terrain and design speeds, with up to 6% generally allowed in mountainous areas and hilly urban areas with exceptions for up to 7% grades on mountainous roads with speed limits below 60 mph (95 km/h). The steepest roads in
660-433: A week. Schools were closed, and a "state of emergency" was declared. The winds grounded planes at LAX, destroyed homes, and were even strong enough to snap a concrete stop light from its foundation. The winds also ripped through Mammoth Mountain and parts of Utah. Mammoth Mountain experienced a near-record wind gust of 175 mph (282 km/h), on December 1, 2011. Because they are simultaneous "gusty" and "desiccating,"
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#1732772415536720-739: Is 23.1% by the 67-Bernal Heights on Alabama Street between Ripley and Esmeralda Streets. Likewise, the Pittsburgh Department of Engineering and Construction recorded a grade of 37% (20°) for Canton Avenue. The street has formed part of a bicycle race since 1983. Grade, pitch, and slope are important components in landscape design , garden design , landscape architecture , and architecture ; for engineering and aesthetic design factors. Drainage, slope stability, circulation of people and vehicles, complying with building codes, and design integration are all aspects of slope considerations in environmental design . Ruling gradients limit
780-619: Is a strong, warm, and very dry wind blowing out of the bottom of mountain passes into the valleys and coastal plain. These warm, dry winds, which can easily exceed 40 miles per hour (64 km/h), can severely exacerbate brush or forest fires, especially under drought conditions. During Santa Ana conditions it is typically hotter along the coast than in the deserts, with the Southern California coastal region reaching some of its highest annual temperatures in autumn rather than summer. Frigid, dry arctic air from Canada tends to create
840-465: Is advised that boaters moor on the Southern side of affected islands or return to the mainland. A Santa Ana fog is a derivative phenomenon in which a ground fog settles in coastal Southern California at the end of a Santa Ana wind episode. When Santa Ana conditions prevail, with winds in the lower two to three kilometers (1.25-1.8 miles) of the atmosphere from the north through east, the air over
900-654: Is expressed as a percentage, the angle can be determined as: If the angle is expressed as a ratio (1 in n) then: For degrees, percentage (%) and per-mille (‰) notations, larger numbers are steeper slopes. For ratios, larger numbers n of 1 in n are shallower, easier slopes. The examples show round numbers in one or more of the notations and some documented and reasonably well known instances. In vehicular engineering , various land -based designs ( automobiles , sport utility vehicles , trucks , trains , etc.) are rated for their ability to ascend terrain . Trains typically rate much lower than automobiles. The highest grade
960-845: Is intended to primarily benefit the mountain lion population indigenous to the Santa Monica Mountains, which has declined due to the Ventura Freeway acting as a barrier in the wildlife corridor between the Simi Hills to the north and the Santa Monica Mountains to the south. The Ventura County Transportation Commission , CalTrans , and the National Park Service , with support from the National Wildlife Federation , are considering building another wildlife crossing here to connect
1020-560: Is likely a false etymology . In 1933, Father John O'Connell of Mission San Juan Capistrano reported that Don Jesus Aguilar, born 1855 at Capistrano, said that in his day the winds had been called el viento del norte . Santa Ana winds are widely believed to affect people's moods and behavior. The Santa Ana winds are commonly portrayed in fiction as being responsible for a tense, uneasy, wrathful mood among Angelenos. As The New York Times put it in 2003, "a dry, hot Santa Ana often symbolizes an unnamable menace lying just beneath
1080-554: The Riverside Press-Enterprise in 2020: According to research done by Orange County historian Chris Jepsen, the first reported reference to that term comes to us in 1871 from the Anaheim Gazette . To anyone in what would become Orange County at the time, the winds seem to come out of Santa Ana Canyon, hence the name. However, having Santa Ana winds named for their city did not please the members of
1140-464: The Santa Barbara and Goleta area occur most frequently in the late spring to early summer, and are strongest at sunset, or "sundown"; hence their name: sundowner. Because high pressure areas usually migrate east, changing the pressure gradient in Southern California to the northeast, it is common for "sundowner" wind events to precede Santa Ana events by a day or two. The Santa Ana winds and
1200-605: The Sierra Nevada and into the Southern California region. According to one meteorology journal, "a popular rule of thumb used by forecasters is to measure the difference in pressure between the Los Angeles International Airport and Las Vegas ; a difference of 9 millibars (0.27 inches of mercury ) is enough to support a Santa Ana event." Dry air flows outward in a clockwise spiral from the high pressure center. This dry airmass sweeps across
1260-431: The chaparral into explosive fuel feeding the infamous wildfires for which the region is known. Although the winds often have a destructive nature, they have some benefits as well. They cause cold water to rise from below the surface layer of the ocean, bringing with it many nutrients that ultimately benefit local fisheries. As the winds blow over the ocean, sea surface temperatures drop about 4 °C (7 °F ), indicating
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#17327724155361320-424: The perpendicular cross slope . There are several ways to express slope: Any of these may be used. Grade is usually expressed as a percentage, but this is easily converted to the angle α by taking the inverse tangent of the standard mathematical slope, which is rise / run or the grade / 100. If one looks at red numbers on the chart specifying grade, one can see the quirkiness of using the grade to specify slope;
1380-694: The upwelling . Chlorophyll concentrations in the surface water go from negligible, in the absence of winds, to very active at more than 1.5 milligrams per cubic meter in the presence of the winds. During the Santa Ana winds, large ocean waves can develop. These waves come from a northeasterly direction toward the normally sheltered sides of the Channel Islands , including commonly visited Catalina and Santa Cruz islands. Normally well-sheltered harbors and anchorages such as Avalon and Two Harbors can develop high surf and strong winds that can tear boats from their moorings. During Santa Ana conditions, it
1440-410: The 1930s. Caltrans worked on the current grade setup, when the highway was brought to freeway standards in the 1950s. Portions of the original highway continue to receive use as side roads. By 2017, the National Park Service has recorded a dozen mountain lions struck and killed by motorists on this section of freeway since 2002 when they began the study. Brother and sister, P-32 and P-33, crossed
1500-698: The Chamber of Commerce in the city of Santa Ana , and they fought for years to get the name changed. The name Santa Ana wind became nationally known following a sensationalized 1901 wire story about wind damage. One narrative claimed that the term Santa Ana wind derives from a Native American phrase for "devil wind" that was then altered by Californios into the form "Satanás" (meaning Satan ), and then still later corrupted into "Santa Ana". However, an authority on local Native American languages claims this supposed Indigenous term "Santana" never existed. No evidence has ever emerged to support this explanation and it
1560-466: The Great Western main line, nicknamed Brunel's Billiard Table, because the early locomotives (and their brakes) were feeble. Steep gradients were concentrated in short sections of lines where it was convenient to employ assistant engines or cable haulage , such as the 1.2 kilometres (0.75 miles) section from Euston to Camden Town . Extremely steep gradients require the use of cables (such as
1620-639: The Guinness Book. Drawing on the U.S. National Elevation Dataset, 7x7 (magazine) identified ten blocks of public streets in San Francisco open to vehicular traffic in the city with grades over 30 percent. The steepest at 41 percent is the block of Bradford Street above Tompkins Avenue in the Bernal Heights neighborhood. The San Francisco Municipal Railway operates bus service among the city's hills . The steepest grade for bus operations
1680-648: The Los Angeles Basin was primarily an agricultural region, the winds were feared particularly by farmers for their potential to destroy crops. In early December 2011, the Santa Ana winds were the strongest yet recorded. An atmospheric set-up occurred that allowed the towns of Pasadena and Altadena in the San Gabriel Valley to get whipped by sustained winds at 97 mph (156 km/h), and gusts up to 167 mph (269 km/h). The winds toppled thousands of trees, knocking out power for over
1740-655: The Pacific Coast around Los Angeles from inland desert regions". Santa Ana winds originate from high-pressure airmasses over the Great Basin and upper Mojave Desert. Any low-pressure area over the Pacific Ocean, off the coast of California, can change the stability of the Great Basin High, causing a pressure gradient that turns the synoptic scale winds southward down the eastern side of
1800-666: The Potrero grade, they decided to construct a new route into the Santa Rosa Valley . The Norwegian Grade was carved out of a steep canyon hillside by members of the community and their hired help between 1900 and 1911. Land for the highway was originally part of the Rancho El Conejo , with contributions from Adolfo Camarillo . A road was in place by no later than 1929, as a re-alignment had been done then. Further widening and reduction of blind curves occurred in
1860-487: The Santa Ana starts to blow, I invariably grow edgy...unable, in the most concrete sense, to settle myself down." There was a desert wind blowing that night. It was one of those hot dry Santa Anas that come down through the mountain passes and curl your hair and make your nerves jump and your skin itch. On nights like that every booze party ends in a fight. Meek little wives feel the edge of the carving knife and study their husbands' necks. Anything can happen. You can even get
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1920-667: The Santa Ana winds are highly associated with regional wildfire danger. The winds have been implicated in some of the area's (and even the state's) largest and deadliest wildfires , including the Thomas Fire , and Cedar Fire , as well as the Laguna Fire , Old Fire , Esperanza Fire , and the Witch Creek Fire . Other major wildfires fueled by Santa Ana winds include: The winds carry Coccidioides immitis and Coccidioides posadasii spores into nonendemic areas,
1980-684: The Scenic Railway at Katoomba Scenic World , Australia, with a maximum grade of 122% (52°), claimed to be the world's steepest passenger-carrying funicular ) or some kind of rack railway (such as the Pilatus railway in Switzerland, with a maximum grade of 48% (26°), claimed to be the world's steepest rack railway ) to help the train ascend or descend. Gradients can be expressed as an angle, as feet per mile, feet per chain, 1 in n , x % or y per mille. Since designers like round figures,
2040-639: The accompanying raging wildfires have been a part of the ecosystem of the Los Angeles Basin for over 5,000 years, dating back to the earliest habitation of the region by the Tongva and Tataviam peoples. The Santa Ana winds have been recognized and reported in English-language records as a weather phenomenon in Southern California since at least the mid-nineteenth century. During the Mexican–American War , Commodore Robert Stockton reported that
2100-554: The body, causing skin ulcers, abscesses, bone lesions, severe joint pain, heart inflammation, urinary tract problems, meningitis, and often death. The best-accepted explanation for the name Santa Ana winds is that it is derived from the Santa Ana Canyon in Orange County , one of the many locations where the winds blow intensely. Newspaper references to the name Santa Ana winds appear as far back as 1882. Per
2160-615: The coast pulls the airmass offshore. Mountain passes which channel these winds include the Soledad Pass , the Cajon Pass , and the San Gorgonio Pass , all well known for exaggerating Santa Anas as they are funneled through. As the wind narrows and is compressed into the passes its velocity increases dramatically, often to near- gale force or above. At the same time, as the air descends from higher elevation to lower,
2220-428: The coastal basin is extremely dry, and this dry air extends out over offshore waters of the Pacific Ocean. When the Santa Ana winds cease, the cool and moist marine layer may re-form rapidly over the ocean if conditions are right. The air in the marine layer becomes very moist and very low clouds or fog occurs. If wind gradients turn on-shore with enough strength, this sea fog is blown onto the coastal areas. This marks
2280-504: The day because the strong offshore desert winds oppose the on-shore sea breeze. At night, the Santa Ana Winds merge with the land breeze blowing from land to sea and strengthen because the inland desert cools more than the ocean due to differences in the heat capacity and because there is no competing sea breeze. Santa Ana winds are associated in the public mind with dry hot weather, but cold Santa Anas not only exist but have
2340-460: The deserts of eastern California toward the coast, and encounters the towering Transverse Ranges , which separate coastal Southern California from the deserts. The airmass, flowing from high pressure in the Great Basin to a low pressure center off the coast, takes the path of least resistance by channeling through the mountain passes to the lower coastal elevations, as the low pressure area off
2400-435: The edge we are. When the hills of Los Angeles are burning Palm trees are candles in the murder winds So many lives are on the breeze/ Even the stars are ill at ease And Los Angeles is burning. Some of this experienced mood shift is likely due to the increase of static electricity in dry conditions. California folklore therefore credits the winds with "strange luminosity in the form of sparks and glows that accompany
2460-643: The freeway in 2015 and became the first Santa Monica Mountains pumas with a tracking collar to cross a freeway in six years. A young male mountain lion, P-55, left the Santa Monica Mountains in 2017 by crossing the freeway on the grade during the night. The animals was wearing a tracking collar used by the National Park researchers studying the mountain lions in the Santa Monica Mountains National Recreation Area . The proposed Wallis Annenberg Wildlife Crossing
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2520-416: The gradient through the platform was eased from 1 in 80 to 1 in 130. Santa Ana Winds The Santa Ana winds , also sometimes called the devil winds , are strong, extremely dry downslope winds that originate inland and affect coastal Southern California and northern Baja California . They originate from cool, dry high-pressure air masses in the Great Basin . Santa Ana winds are known for
2580-453: The high pressure system over the Great Basin, which caused the Santa Ana conditions in the first place, is slow to weaken or move east across the United States. In this more usual case, the Santa Ana winds cease, but warm, dry conditions under a stationary air mass continue for days or even weeks after the Santa Ana wind event ends. A related phenomenon occurs when the Santa Ana condition is present but weak, allowing hot dry air to accumulate in
2640-463: The horizontal run by using the Pythagorean theorem, after which it is trivial to calculate the (standard math) slope or the grade (percentage). In Europe, road gradients are signed as a percentage. Grades are related using the following equations with symbols from the figure at top. The slope expressed as a percentage can similarly be determined from the tangent of the angle: If the tangent
2700-637: The hot, dry weather that they bring in autumn (often the hottest of the year), but they can also arise at other times of the year. They often bring the lowest relative humidities of the year to coastal Southern California, and "beautifully clear skies". These low humidities, combined with the warm, compressionally-heated air mass, plus high wind speeds, create critical fire weather conditions and fan destructive wildfires . Typically, about 10 to 25 Santa Ana wind events occur annually. A Santa Ana can blow from one to seven days, with an average wind event lasting three days. The longest recorded Santa Ana event
2760-480: The inland valleys that may not push all the way to sea level. Under these conditions auto commuters can drive from the San Fernando Valley where conditions are sunny and warm, over the low Santa Monica Mountains, to plunge into the cool cloudy air, low clouds, and fog characteristic of the marine air mass. This and the "Santa Ana fog" above constitute examples of an air inversion . The similar winds in
2820-546: The load that a locomotive can haul, including the weight of the locomotive itself. On a 1% gradient (1 in 100) a locomotive can pull half (or less) of the load that it can pull on level track. (A heavily loaded train rolling at 20 km/h on heavy rail may require ten times the pull on a 1% upgrade that it does on the level at that speed.) Early railways in the United Kingdom were laid out with very gentle gradients, such as 0.07575% (1 in 1320) and 0.1515% (1 in 660) on
2880-753: The method of expression can affect the gradients selected. The steepest railway lines that do not use a rack system include: Gradients on sharp curves are effectively a bit steeper than the same gradient on straight track, so to compensate for this and make the ruling grade uniform throughout, the gradient on those sharp curves should be reduced slightly. In the era before they were provided with continuous brakes , whether air brakes or vacuum brakes , steep gradients made it extremely difficult for trains to stop safely. In those days, for example, an inspector insisted that Rudgwick railway station in West Sussex be regraded. He would not allow it to open until
2940-521: The most intense Santa Ana winds. While the Santa Anas are katabatic, they are not Föhn winds . These result from precipitation on the windward side of a mountain range which releases latent heat into the atmosphere which is then warmer on the leeward side (e.g., the Chinook or the original Föhn). If the Santa Anas are strong, the usual day-time sea breeze may not arise, or develop weak later in
3000-742: The natural habitat on both sides of the freeway. The Hill Fire temporarily closed the freeway on November 8, 2018, as Santa Ana Winds pushed the fire to the south towards Newbury Park and California State University Channel Islands . The fire was contained with minimal damage on November 16. The Woolsey Fire started the same day, closed the freeway near Oak Park , grew to over 98,362 acres (39,806 hectares), destroyed an estimated 616 structures, and killed 3 people. 34°12′1″N 118°57′34″W / 34.20028°N 118.95944°W / 34.20028; -118.95944 Grade (slope) The grade (US) or gradient (UK) (also called stepth , slope , incline , mainfall , pitch or rise ) of
3060-400: The numbers go from 0 for flat, to 100% at 45 degrees, to infinity as it approaches vertical. Slope may still be expressed when the horizontal run is not known: the rise can be divided by the hypotenuse (the slope length). This is not the usual way to specify slope; this nonstandard expression follows the sine function rather than the tangent function, so it calls a 45 degree slope
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#17327724155363120-736: The sine of the angle rather than the tangent) makes only an insignificant difference and can then be used as an approximation. Railway gradients are often expressed in terms of the rise in relation to the distance along the track as a practical measure. In cases where the difference between sin and tan is significant, the tangent is used. In either case, the following identity holds for all inclinations up to 90 degrees: tan α = sin α 1 − sin 2 α {\displaystyle \tan {\alpha }={\frac {\sin {\alpha }}{\sqrt {1-\sin ^{2}{\alpha }}}}} . Or more simply, one can calculate
3180-413: The slope) and rise is the vertical distance. Slopes of existing physical features such as canyons and hillsides, stream and river banks , and beds are often described as grades, but typically the word "grade" is used for human-made surfaces such as roads, landscape grading, roof pitches , railroads , aqueducts , and pedestrian or bicycle routes. The grade may refer to the longitudinal slope or
3240-1007: The sun-shot surface of California life." According to the Pasadena Public Library [ Wikidata ] book blog, the winds notably appear in Richard Henry Dana 's Two Years Before the Mast , the Philip Marlowe story "Red Wind" by Raymond Chandler , three essays by Joan Didion about Los Angeles, ("Los Angeles Notebook" and "Some Dreamers of the Golden Dream", both included in her 1968 book Slouching Towards Bethlehem , and "Fire Season", included in her 1992 book After Henry ), The Husband by Dean Koontz , White Oleander by Janet Fitch , and Less than Zero by Bret Easton Ellis . In Thomas Pynchon 's 2009 "California novel" Inherent Vice
3300-461: The temperature and barometric pressure increase adiabatically , warming about 5 °F for each 1,000 feet it descends (1 °C for each 100 m). Relative humidity decreases with the increasing temperature. The air has already been dried by orographic lift before reaching the Great Basin, as well as by subsidence from the upper atmosphere, so this additional warming often causes relative humidity to fall below 10 percent. The end result
3360-483: The upper terminus of the grade. The Conejo Mountain has functioned as a barrier by separating Ventura County into East County and West County. Historically, the mountain was known for its many jackrabbits and prickly pear cacti. The surrounding area was formed by volcanic eruptions millions of years ago, a rare geological formation in Southern California. Within the traditional lands of the Chumash people , they had
3420-419: The winds make an appearance and, per one scholar, "the obligatory noir description of their effects appears on page 98." Los Angeles Times columnist David L. Ulin commented, "...for writers such as Didion and Chandler, the Santa Ana is an emblem of disruption because, for them, Los Angeles is a disrupted world. We can take issue with that impression of the city; I sometimes do and sometimes don't. But when
3480-715: The world according to the Guinness Book of World Records are Baldwin Street in Dunedin, New Zealand, Ffordd Pen Llech in Harlech, Wales and Canton Avenue in Pittsburgh, Pennsylvania. The Guinness World Record once again lists Baldwin Street as the steepest street in the world, with a 34.8% grade (1 in 2.87) after a successful appeal against the ruling that handed the title, briefly, to Ffordd Pen Llech . A number of streets elsewhere have steeper grades than those listed in
3540-1043: Was a 14-day wind in November 1957. Damage from high winds is most common along the Santa Ana River basin in Orange County, the Santa Clara River basin in Ventura and Los Angeles County , through Newhall Pass into the San Fernando Valley of Los Angeles County, and through the Cajon Pass into San Bernardino County near San Bernardino , Fontana , and Chino . The Santa Anas are katabatic winds (Greek for "flowing downhill") arising in higher altitudes and blowing down towards sea level. The National Weather Service defines Santa Ana winds as "a weather condition [in southern California] in which strong, hot, dust-bearing winds descend to
3600-701: Was a mile shorter and only had twelve curves. Designated as part of the commemorative route of El Camino Real , the steep slope or grade was called the "cuesta del conejo" (slope of the rabbit). Early European settlers in the Conejo Valley, known as the Norwegian Colony , needed a safe way to move bales of hay and sacks of wheat and barley to the Hueneme Wharf on the Oxnard Plain. After several mishaps while hauling crops down here and at
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