High winds that weather officials have called "life-threatening and destructive" are hitting Southern California Tuesday, sparking a major brush fire in Pacific Palisades and prompting thousands of power outages.

The Santa Ana winds occur when there is high pressure to the east, in the Great Basin, and a low-pressure system off the coast. Air masses move from high pressure to low pressure, and the more extreme the difference in the pressure, the faster the winds blow. Topography also plays a role.

A major Santa Ana windstorm that has fanned destructive wildfires while also downing trees and knocking out power in Southern California continues Wednesday, but will ease some as we head into Thursday.

While the cause of each blaze has yet to be determined, all burned in or near foothill communities amid gusty winds and dry air and vegetation.

Strong winds that sent wildfires ripping through the mountains and foothills around Los Angeles on Tuesday fed a spectacle of smoke, flames and flight.