California storm eases but flooding and avalanche risks remain high

A powerful storm system that battered California with heavy winds, rain and snow this week was forecast to ease on Friday, though the risk of high surf along the coast, flash flooding near Los Angeles and avalanches in the Sierra Nevada persisted.

Waves near the San Francisco Bay Area could reach up to 7.6 metres, and avalanches could hit the Lake Tahoe area, officials warned.

Residents were advised to prepare to evacuate the mountain town of Wrightwood, about 130 kilometres northeast of Los Angeles, due to mudslides.

The system also brought the wettest Christmas season to downtown Los Angeles in the last 54 years, the National Weather Service said.

Roads in the 5,000-resident town of Wrightwood were covered in rocks, debris and thick mud on Thursday. With power out, a petrol station and coffee shop running on generators were serving as hubs for residents and visitors.

With more rain on the way, more than 150 firefighters were stationed in the area, said San Bernardino County Fire spokesman Shawn Millerick. “We’re ready,” he said. “It’s all hands on deck at this point.”

Two dead in weather-related incidents

Atmospheric rivers carried massive plumes of moisture from the tropics during one of the busiest travel weeks of the year. The storms were blamed for at least two deaths earlier in the week.

A falling tree killed a San Diego man on Wednesday, news outlets reported. Farther north, a Sacramento sheriff’s deputy died in what appeared to be a weather-related crash.

Areas along the coast, including Malibu, were under a flood watch until Friday afternoon, and wind and flood advisories were issued for much of the Sacramento Valley and the San Francisco Bay Area.

Southern California typically gets 1.3 to 2.5 centimetres of rain this time of year. However, this week many areas could see between 10 and 20 centimetres, with even more in the mountains, US National Weather Service meteorologist Mike Wofford said.

More heavy snow was expected in the Sierra Nevada, where gusts created “near white-out conditions” and made mountain pass travel treacherous.