Understanding the Santa Ana Winds of Southern California
Learn about the meteorological causes, seasonal cycles, and wildfire risks associated with Southern California's powerful winds.
The Meteorology of the Santa Ana Winds
The Santa Ana winds are strong, extremely dry downslope winds that affect Southern California and northern Baja California. They are famous for bringing hot, dry weather in autumn.
1. High Pressure in the Great Basin
The process begins when a high-pressure system builds over the Great Basin (between the Rocky Mountains and the Sierra Nevada). Air is pushed clockwise towards the Pacific ocean.
2. Adiabatic Heating
As the air descends from the high-elevation deserts towards the coast, it is compressed by the atmospheric pressure. This compression heats the air by approximately 5.5°F for every 1,000 feet of descent, making it warm and dry.
3. Wildfire Risks
With wind speeds exceeding 50 mph and relative humidity dropping below 10%, Santa Ana winds create catastrophic fire weather conditions, capable of rapidly spreading sparks into major wildfires.
