The Santa Ana winds are strong extremely dry offshore winds occurring in Southern California and northern Baja California in late fall and winter. The source region of these winds is the Great Basin and upper Mojave Desert; the winds are known for hot dry weather, and extreme wildfire behavior. Santa Ana winds are a type of downslope drainage wind that results from a buildup of air pressure in the high-altitude Grate Basin between the Sierra Nevada and Rocky Mountains. When upper level winds are favorable, the air mass spills out of the Great Basin and is propelled gravitationally towards southern California coastline. The air is heated due to adiabatic heating and compressing and can attain hurricane force at times.
Source: MetEd. 2011. MetEd Education and Training pages. Accessed 23 November 2011. https://www.meted.ucar.edu/