scholarly journals Santa Ana winds and predictors of wildfire progression in southern California

2014 ◽  
Vol 23 (8) ◽  
pp. 1119 ◽  
Author(s):  
Michael Billmire ◽  
Nancy H. F. French ◽  
Tatiana Loboda ◽  
R. Chris Owen ◽  
Marlene Tyner
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Southern California ◽  
Burned Area ◽  
Strong Positive Correlation ◽  
Fuel Temperature ◽  
Fuel Loading ◽  
Fire Event ◽  
Santa Ana ◽  
Santa Ana Winds

Santa Ana winds have been implicated as a major driver of large wildfires in southern California. While numerous anecdotal reports exist, there is little quantitative analysis in peer-reviewed literature on how this weather phenomenon influences fire progression rates. We analysed fire progression within 158 fire events in southern California as a function of meteorologically defined Santa Ana conditions between 2001 and 2009. Our results show quantitatively that burned area per day is 3.5–4.5 times larger on Santa Ana days than on non-Santa Ana days. Santa Ana definition parameters (relative humidity, wind speed) along with other predictor variables (air temperature, fuel temperature, 10-h fuel moisture, population density, slope, fuel loading, previous-day burn perimeter) were tested individually and in combination for correlation with subsets of daily burned area. Relative humidity had the most consistently strong correlation with burned area per day. Gust and peak wind speed had a strong positive correlation with burned area per day particularly within subsets of burned area representing only the first day of a fire, >500 ha burned areas, and on Santa Ana days. The suite of variables comprising the best-fit generalised linear model for predicting burned area (R2 = 0.41) included relative humidity, peak wind speed, previous-day burn perimeter and two binary indicators for first and last day of a fire event.

scholarly journals Hot and cold flavors of southern California’s Santa Ana winds: their causes, trends, and links with wildfire

2021 ◽  
Author(s):  
Alexander Gershunov ◽  
Janin Guzman Morales ◽  
Benjamin Hatchett ◽  
Kristen Guirguis ◽  
Rosana Aguilera ◽  
...  
Keyword(s):  
Great Basin ◽  
Heat Waves ◽  
Early Warning Systems ◽  
High Amplitude ◽  
Warming Trend ◽  
Snow Accumulation ◽  
Burned Area ◽  
Rossby Wave Breaking ◽  
Santa Ana ◽  
Santa Ana Winds

AbstractSanta Ana winds (SAWs) are associated with anomalous temperatures in coastal Southern California (SoCal). As dry air flows over SoCal’s coastal ranges on its way from the elevated Great Basin down to sea level, all SAWs warm adiabatically. Many but not all SAWs produce coastal heat events. The strongest regionally averaged SAWs tend to be cold. In fact, some of the hottest and coldest observed temperatures in coastal SoCal are linked to SAWs. We show that hot and cold SAWs are produced by distinct synoptic dynamics. High-amplitude anticyclonic flow around a blocking high pressure aloft anchored at the California coast produces hot SAWs. Cold SAWs result from anticyclonic Rossby wave breaking over the northwestern U.S. Hot SAWs are preceded by warming in the Great Basin and dry conditions across the Southwestern U.S. Precipitation over the Southwest, including SoCal, and snow accumulation in the Great Basin usually precede cold SAWs. Both SAW flavors, but especially the hot SAWs, yield low relative humidity at the coast. Although cold SAWs tend to be associated with the strongest winds, hot SAWs tend to last longer and preferentially favor wildfire growth. Historically, out of large (> 100 acres) SAW-spread wildfires, 90% were associated with hot SAWs, accounting for 95% of burned area. As health impacts of SAW-driven coastal fall, winter and spring heat waves and impacts of smoke from wildfires have been recently identified, our results have implications for designing early warning systems. The long-term warming trend in coastal temperatures associated with SAWs is focused on January–March, when hot and cold SAW frequency and temperature intensity have been increasing and decreasing, respectively, over our 71-year record.

The Santa Ana Winds of Southern California

Weatherwise ◽  
1962 ◽  
Vol 15 (3) ◽  
pp. 102-121 ◽  
Author(s):  
Leo A. Sergius ◽  
George R. Ellis ◽  
Richard M. Ogden
Keyword(s):  
Southern California ◽  
Santa Ana ◽  
Santa Ana Winds

Analysis of the effects of combustion emissions and Santa Ana winds on ambient ozone during the October 2007 southern California wildfires

2010 ◽  
Vol 44 (5) ◽  
pp. 678-687 ◽  
Author(s):  
Andrzej Bytnerowicz ◽  
Dan Cayan ◽  
Philip Riggan ◽  
Susan Schilling ◽  
Philip Dawson ◽  
...  
Keyword(s):  
Southern California ◽  
Santa Ana ◽  
Ambient Ozone ◽  
Santa Ana Winds ◽  
Combustion Emissions

scholarly journals Diagnosing Santa Ana Winds in Southern California with Synoptic-Scale Analysis

2013 ◽  
Vol 28 (3) ◽  
pp. 704-710 ◽  
Author(s):  
John T. Abatzoglou ◽  
Renaud Barbero ◽  
Nicholas J. Nauslar
Keyword(s):  
Sea Level ◽  
Southern California ◽  
The United States ◽  
Fire Weather ◽  
Synoptic Scale ◽  
Sea Level Pressure ◽  
Mean Sea Level ◽  
Santa Ana ◽  
Level Pressure ◽  
Santa Ana Winds

Abstract Santa Ana winds (SAW) are among the most notorious fire-weather conditions in the United States and are implicated in wildfire and wind hazards in Southern California. This study employs large-scale reanalysis data to diagnose SAW through synoptic-scale dynamic and thermodynamic factors using mean sea level pressure gradient and lower-tropospheric temperature advection, respectively. A two-parameter threshold model of these factors exhibits skill in identifying surface-based characteristics of SAW featuring strong offshore winds and extreme fire weather as viewed through the Fosberg fire weather index across Remote Automated Weather Stations in southwestern California. These results suggest that a strong northeastward gradient in mean sea level pressure aligned with strong cold-air advection in the lower troposphere provide a simple, yet effective, means of diagnosing SAW from synoptic-scale reanalysis. This objective method may be useful for medium- to extended-range forecasting when mesoscale model output may not be available, as well as being readily applied retrospectively to better understand connections between SAW and wildfires in Southern California.

Effects to Forest Fire Occurrence of Climate Change in Ta He Forestry Bureau in Great Xing’an Mountain

2011 ◽  
Vol 183-185 ◽  
pp. 135-139
Author(s):  
Zhan Shu ◽  
Xue Ying Di ◽  
Hui Huang
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Forest Fire ◽  
Forest Fires ◽  
Ecological Factors ◽  
Burned Area ◽  
Fire Cycle ◽  
Julian Date ◽  
Linear Relationships ◽  
The Relationship

Forest fire is one of the most important ecological factors in the forest ecosystem. The Great Xing’an Mountain region has not only the largest forest areas, but also the biggest forest fire burned area in China. By analyzing the recorded climate and forest fire data of Ta He forestry bureau from 1974 to 2004, the following results can be concluded: (1) There were 298 forest fires recorded by Ta He forestry bureau during 31 years and the burned area were 1.63 million hectares totally with 9.6 forest fires per year, unpredictable and short fire cycle as characters. (2) According to the occurrence time of forest fires, the Julian date concentrated between 102~181 and 240~293, corresponding April 12th to June 30th and August 28th to October 20th, which were spring and autumn fire prevention periods. Major fires mainly occurred in spring of 1974~1982, 1986~1987, 1993, and 1998~2002. The major fires cycle were 4 to 5 years. (3) The related indices of temperature, relative humidity, rainfall, and wind speed recorded in June in Ta He forestry bureau were 0.3929, 0.5274, 0.6136 and 0.1679. Temperature, relative humidity and rainfall factors in June had obvious linear relationships to forest fires, while the relationship between wind speed and forest fires is unobvious.

scholarly journals The health burden of fall, winter and spring heatwaves and contribution of Santa Ana Winds in Southern California

2019 ◽  
Vol 3 ◽  
pp. 357
Author(s):  
Schwarz L ◽  
Malig B ◽  
Guzman-Morales J ◽  
Guirguis K ◽  
Gershunov A ◽  
...  
Keyword(s):  
Southern California ◽  
Santa Ana ◽  
Health Burden ◽  
Santa Ana Winds
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