LOS ANGELES (AP) — A drenching storm that brought California much-needed rain in what had been a dry winter wound down Friday after washing out Highway 1 near Big Sur, burying the Sierra Nevada in snow and causing muddy flows from slopes burned bare by wildfires.
The atmospheric river weather system that barreled ashore in Northern California early in the week rolled quickly through Southern California overnight and was moving east before dawn. Remnants unleashed occasional downpours and hail.
There were no immediate reports of large-scale debris flows in the region, but mud slid off burned slopes in Orange County’s Silverado Canyon and from a fire-scorched hillside onto State Route 39 on the foothills of the San Gabriel Mountains.
About 8,200 residents had been ordered in advance to evacuate from areas near fire scars east of Los Angeles in San Bernardino and Riverside counties.
Flash flood watches remained in effect for parts of Southern California and winter storm and avalanche warnings continued in the Sierra. But most of the state was able to turn to cleanup, damage assessments and tallying astonishing rain and snowfall.
Highway crews were to begin damage assessments Friday and there was no estimate on when the popular driving route would reopen, the California Department of Transportation said.
Central coast rainfall topped 15 inches (38.1 centimeters) when the storm stalled there at midweek, triggering mud flows that damaged about two dozen homes.
The storm also unleashed a huge amount of snow in the Sierra, where the annual snowpack normally provides about a third of the state’s water supply.
The Mammoth Mountain ski resort reported the storm had dropped 8.92 feet (2.72 meters) of snow as of early Friday, with more falling. California Department of Transportation plows worked to clear some mountain highways and others were open with strict chain requirements.
Yosemite National Park officials said the snowstorm would force it to remain closed until at least Feb. 1.
The park has been closed since a huge windstorm hit early last week, knocking down 15 giant sequoias and slamming trees onto trucks and buildings. Damage has been estimated as high as $200 million.
Atmospheric rivers are long, narrow bands of water vapor that form over an ocean and flow through the sky. They occur globally but are especially significant on the West Coast of the United States, where they create 30% to 50% of annual precipitation and are linked to water supply and problems such as flooding and mudslides, according to the National Oceanic and Atmospheric Administration.
The atmospheric river was part of a major change in weather for California, which had significant drought conditions for months. The dryness contributed to wildfires that scorched more than 4.2 million acres (17,000 square kilometers) in 2020, the most in recorded modern history.
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