Powerful Santa Ana winds fuelled wildfires across Southern California even as a welcome shift in moisture moved across the West Coast, bringing the season's first major storm with heavy rain, flash-flood danger and even a rare tornado threat, Fox Weather reported. As numerous wildfires burned across parts of California, a strong upper-level trough moved south along the coast, spreading showers from Northern and Central California into the south by Wednesday.
The National Weather Service issued a slight flash-flood risk, level two of four, for the Central and Southern California coast from Monterey and Big Sur down through Santa Barbara, Malibu, Long Beach and Newport Beach. Most coastal and valley areas in Southern California should see half an inch to an inch and a half of rain, with up to three inches in higher terrain, and the Sierra Nevada could see up to 10 inches of snow. Downtown Los Angeles could record one to one and a half inches through Thursday night, potentially the city's wettest October since 2009.
The greatest concern is over recent burn scars, where heavy bursts threaten the Timber and Plaskett scars on the Big Sur coast. According to the US Geological Survey, just a quarter-inch of rain in 15 minutes could send a slurry of rock and mud across Highway 1. A rare Level 3 severe weather risk was issued for northern Arizona on Wednesday due to elevated chances for damaging winds and tornadoes, Fox Weather reported.
The wet weather will continue Thursday as the upper-level low shifts eastward into Nevada, Utah and Arizona, ABC News reported. The storm marks a sharp turn from the wind-driven fire danger that tested Los Angeles preparedness earlier in the week, though forecasters caution that the same storms bringing relief could also produce damaging wind gusts, small hail and flooding through Friday.