Wildcat Canyon is a narrow linear valley just east of the Berkeley Hills in the San Francisco Bay Area , situated in Contra Costa County, California . The canyon is bounded on its east side by the San Pablo Ridge , and is drained by Wildcat Creek which runs northwest to its outlet in San Pablo Bay . Two minor lakes or ponds lie along the creek: Jewel Lake and Lake Anza . The latter was enlarged by the construction of a small dam in the mid-20th century. An active tectonic fault , the Wildcat Fault, runs the length of the canyon. Wildcat Canyon was named for the mountain lions which used to be fairly common in the area. The southern end of the canyon adjacent to the city of Berkeley was incorporated into Tilden Regional Park in the 1930s and remains a major recreation area for local residents. Another regional park, Wildcat Canyon Regional Park , is situated at the northern end of the canyon.
15-722: On September 17, 1923, a wildfire ignited in Wildcat Canyon during a period of hot, dry Diablo winds and rapidly spread to eucalyptus groves along the crest of the ridge separating the canyon from populated areas of the Berkeley Hills. Continuing into residential areas, by the next day the fire had destroyed 640 structures, including the home of architect Bernard Maybeck and many buildings he had designed. 37°54′59″N 122°16′32″W / 37.91634°N 122.27543°W / 37.91634; -122.27543 This Contra Costa County, California –related article
30-408: A foehn wind. Sundowners are particularly dangerous during wildfire season because the air heats and dries as it descends from the mountains to the sea. Gale force hot, dry winds can make firefighting impossible. A sundowner quickly burned a swath from the mountains through populated areas and across Highway 101 into Hope Ranch during the 1990 Painted Cave Fire . The most intense periods of
45-505: A region of high pressure is directly north of the area, the coast of which trends east–west. This contrasts with the more typical onshore flow. The winds blow with greatest force when the pressure gradient is perpendicular to the axis of the Santa Ynez Mountains, which rise directly behind Santa Barbara. These winds often precede Santa Ana events by a day or two, but also as tail end of Santa Anas after they weaken, it
60-656: A Diablo wind is first noted and blows strongest atop the various mountain peaks and ridges around the Bay Area. In both cases, as the air sinks, it heats up by compression and its relative humidity drops. This warming is in addition to, and usually greater than, any contact heating that occurs as the air stream crosses the Central Valley and the Diablo Valley. This is the reverse of the normal summertime weather pattern in which an area of low pressure (called
75-555: A few weeks with a lull in between as solar incidence declines. Southern Californian coasts from Ventura County south are generally unaffected by Diablo events. Sundowner winds A sundowner is a northerly offshore wind in California along the southern Pacific slope of Santa Ynez Mountains , in communities along the Gaviota Coast and Santa Barbara towards but not including Ventura County . It occurs when
90-535: A phenomenon called the " hydraulic jump ". While hydraulic jumps can occur with Santa Ana winds, the same thermodynamic structure that occurs with them typically favors "gap" flow more frequently. Santa Ana winds are katabatic , gravity-driven winds, draining air off the high deserts, while the Diablo-type wind originates mainly from strongly sinking air from aloft, pushed toward the coast by higher pressure aloft. Thus, Santa Anas are strongest in canyons, whereas
105-524: Is a stub . You can help Misplaced Pages by expanding it . Diablo wind Diablo wind is a name that has been occasionally used for the hot, dry wind from the northeast that typically occurs in the San Francisco Bay Area of Northern California during the spring and fall. The same wind pattern also affects other parts of California's coastal ranges and the western slopes of Sierra Nevada , with many media and government groups using
120-932: Is also typically the case that sundowner winds commence in the evening near sunset, when onshore sea breezes abate and offshore flows such as the sundowners pick up. As sundowner events typically happen near nighttime or during nighttime, when coastal temperatures die down, there can be a sharp temperature difference in monitoring stations merely blocks away, due to elevation difference. Higher elevations of hills can correlate with huge temperature rises compared with lower elevations, and can rival those seen in daytime heatwaves --- coastal inversion layer kept beaches (Pacific side of San Francisco) some 40 to 45 degrees fahrenheit cooler than hills at 2500 or 5000 feet (Mount Tamalpais) on afternoon of July 6 2024. Sundowners have caused similarly intense [ sharp temperature contrasts ] akin to these daytime inversion layers, but surprisingly at close to midnight, where California State Route 192 approximates
135-407: Is normal for high-pressure areas to migrate east, causing the pressure gradients to shift to the northeast. Aptly named sundowners are typically nighttime events that terminate after sunrise, they may repeat for days, while Santa Anas are multi-day long events. Weaker sundowner effects may occur without an associated Santa Ana event, at times due to a Diablo wind event (Northern California), akin to
150-616: The Jesusita Fire 's destruction have also been blamed on sundowner winds. The Sherpa Fire grew to 4,000 acres (1,600 ha) overnight due to the sundowner winds, destroying the water system for El Capitán State Beach at the beginning of the 2016 fire season. The etymology of the word sundowner is uncertain, but it may derive from the Spanish term zonda , or from the Arabic simoom , which are both similar wind phenomena. It
165-596: The California Thermal Low) rather than high pressure lies east of the Bay Area, drawing in cooler, more humid air from the ocean. The dry offshore wind, already strong because of the offshore pressure gradient, can become quite strong with gusts reaching speeds of 40 miles per hour (64 km/h) or higher, particularly along and in the lee of the ridges of the Coast Range . This effect is especially dangerous with respect to wildfires as it can enhance
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#1732772472745180-609: The California coast. The air descending from aloft as well as from the Coast Ranges compresses as it sinks to sea level where it warms as much as 20 °F (11 °C), and loses relative humidity. Because of the elevation of the coastal ranges in north-central California, the thermodynamic structure that occurs with the Diablo wind pattern favors the development of strong ridge-top and lee-side downslope winds associated with
195-440: The one that was associated with the 1923 Berkeley Fire . The name "Diablo wind" refers to the fact that the wind blows into the inner Bay Area from the direction of Mount Diablo in adjacent Contra Costa County and evoking the fiery, sensationalist connotation inherent in "devil wind". The Diablo wind is created by the combination of strong inland high pressure at the surface, strongly sinking air aloft, and lower pressure off
210-570: The term Diablo winds for strong, dry downslope wind over northern and central California. The term first appeared shortly after the 1991 Oakland firestorm , perhaps to distinguish it from the comparable, and more familiar, hot dry wind in Southern California known as the Santa Ana winds . In fact, in decades previous to the 1991 fire, the term "Santa Ana" was occasionally used as well for the Bay Area dry northeasterly wind, such as
225-565: The updraft generated by the heat in such fires. While the Diablo wind pattern occurs in both the spring and fall, it is most dangerous in the fall, when vegetation is at its driest. California's predominantly Mediterranean climate has an extended dry period from May through October. Effects tend to be halved at farther southern coasts, and even can spawn Sundowner winds in Santa Barbara. Although Santa Ana winds may recur, Diablo events in autumn tend to precede Santa Ana wind events by
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