Santa Ana winds are strong, hot, dust-bearing winds that descend toward the Pacific Coast around Los Angeles from inland desert regions. The winds often pass through Santa Ana Canyon, just east of Los Angeles.
The weather condition is most common from October through March, when the desert is relatively cold. The winds develop as high pressure builds over Nevada’s Great Basin, according to the UCLA Department of Atmospheric and Oceanic Sciences.
Carol Smith, a meteorologist with the National Weather Service, says that one risk with existing fires is that Santa Ana winds can lead to extreme fire behavior, which includes fire whirls and pyrocumulus clouds, which can produce lightning and thunder.
“Fuel moisture is very low, which means those fuels are ready. If there’s any kind of spark, or something to start a fire, those fuels are primed and ready to just take off,” Smith said.
In the wake of a hot, dry summer, the absence of rain could prove disastrous.
“The fires can grow 1,000 acres in one hour, so it is critical to get suppression ASAP, especially in Santa Ana dry wind and warm conditions,” said Alex Tardy, the warning coordination meteorologist with the NWS in San Diego. “The summer of 2021 was the warmest on record for mountains and deserts, so that is much extra stress on the vegetation. The winter of 2020-21 was about 40 to 50% of average rainfall (dry water year), so that also adds to more stress and drying of fuels (live or dead fuels).”
California relies on weather events called atmospheric rivers — narrow regions in the atmosphere that transport water vapor — to provide much needed water to reservoirs, lakes and agriculture. This past year was dismal, with only two of these strong events occurring in Southern California. The region normally averages seven per year.
The bigger concern is what the future holds.