When fall rolls around in Southern California, bone-dry conditions set the stage for massive wildfires, and the Santa Ana winds are the fuel that fans the flames.
Easterly winds bring dry air from the desert that is then forced down over the San Gabriel and San Bernadino mountains, drying it further. The wind gets funneled through those mountain passes, causing wind gusts up to 70 mph, according to AccuWeather chief meteorologist Bernie Rayno.
When those heavy winds are accompanied by low humidity and high temperatures, the Southern California region is at a significant risk for wildfires.
When the humidity drops to single-digit percentages, vegetation both living and dead is significantly dried out, making it even more flammable.
The origin of the wind's name has never been settled, but most discussions mention Santa Ana Canyon in Orange County, southeast of Los Angeles.
The Associated Press contributed to this report.