Climate and weather drivers in southern California Santa Ana Wind and non-Santa Wind fires

Jon E. Keeley; Michael Flannigan; Tim J. Brown; Tom Rolinski; Daniel Cayan; Alexandra D. Syphard; Janin Guzman-Morales; Alexander Gershunov

doi:10.1071/wf23190

USGS · 70257564

Climate and weather drivers in southern California Santa Ana Wind and non-Santa Wind fires

Jon E. Keeley·Michael Flannigan·Tim J. Brown·Tom Rolinski·Daniel Cayan·Alexandra D. Syphard·Janin Guzman-Morales·Alexander Gershunov

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Abstract

Background. Autumn and winter Santa Ana Winds (SAW) are responsible for the largest and most destructive wildfires in southern California. Aims. 1) To contrast fires ignited on SAW days vs non-SAW days, 2) evaluate the predictive ability of the Canadian Fire Weather Index (CFWI) for these two fire types, and 3) determine climate and weather factors responsible for the largest wildfires. Methods. Cal Fire FRAP fire data were coupled with hourly climate data from 4 stations, and with regional indices of SAW wind speed, and with seasonal drought from the Palmer Drought Severity Index. Key results. Fires on non-SAW days were more numerous and burned more area, and were significant May to October. CFWI indices were tied to fire occurrence and size for both non-SAW and SAW days, and in the days following ignition. Multiple regression models for months with greatest area burned explained up to a quarter of variation in area burned. Conclusions. The drivers of fire size differ between non-SAW and SAW fires. The best predictor of fire size for non-SAW fires was drought during the prior five years, followed by current-year vapor pressure deficit. For SAW fires, wind speed followed by drought were most important.

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International Journal of Wildland Fire Article

Source-reported bounding extent: 32.577742693551556° to 35.25764436587998° latitude; -120.89507141501502° to -116.66533508689008° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Jon E. Keeley, Michael Flannigan, Tim J. Brown, Tom Rolinski, Daniel Cayan, Alexandra D. Syphard, Janin Guzman-Morales, Alexander Gershunov. 2024-08-15. Climate and weather drivers in southern California Santa Ana Wind and non-Santa Wind fires. https://doi.org/10.1071/wf23190

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