Avalanche, Flooding Risk High As New Atmospheric River Pounds CA

CALIFORNIA — Another atmospheric river slammed into California on Friday, prompting officials to declare a state of emergency in several counties as heavy rain, thunderstorms and strong winds battered parts of the state still recovering from multiple bouts of severe winter weather.

The atmospheric river, known as a "Pineapple Express" because it brought warm subtropical moisture across the Pacific from near Hawaii, was melting lower parts of the vast snowpack built in California's mountains by nine atmospheric rivers early in the winter and later storms fueled by a blast of arctic air.

At least one person died Friday when strong winds caused the roof of an Oakland warehouse to collapse. Another person suffered minor injuries, according to officials.

Meanwhile, at least 13 others have died in the wake of back-to-back storms that brought blizzard conditions to California's mountain communities, police said.

On Friday, heavy rain created catastrophic and life-threatening flooding across California, prompting officials to issue flood advisories and warnings for areas around the San Francisco Bay, the central coast and the Sacramento and San Joaquin valleys.

In Soquel, a town in Santa Cruz County, a portion of Main Street was thoroughly washed away by floodwaters Friday morning, according to Accuweather. Meanwhile, evacuation warnings were issued in advance for various foothill and mountain communities prone to flooding and mudslides. An evacuation order was also in place for a small number of central coast residents who live below a levee near Oceano in San Luis Obispo County.

National Weather Service forecasters said the bulk of the rain from the storm would remain north of the Los Angeles area, according to Accuweather.

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Avalanche warnings were put in place Friday after recent storms dumped more than 100 inches of snow on some mountain communities, resulting in several "weak layers" of snow. Additional heavy snow was expected through Friday, increasing the danger of avalanches, the Eastern Sierra Avalanche Center told Accuweather.

As of Friday morning, the avalanche warning remained "high" but was expected to increase to "extreme" by Friday afternoon and evening.

Forecasters warned that mountain travel could be difficult to impossible during the latest storm. At high elevations, the storm was predicted to dump as much as 8 feet of new snow over several days.

California's Sierra Nevada snowpack, which provides about a third of the state's water supply, is more than 180 percent of the April 1 average, when it is historically at its peak.

In Southern California, forecasters said there would be a "significant drop off in the rain" south of Point Conception.

"While the duration of rain will be similar, rain rates will take a huge hit, down to mostly under a third of an inch per hour, as there is very little upslope flow there," according to the NWS. "Most populated areas in LA County are expected to get an inch or less from this storm and up to around 2 inches in the mountains. And no snow from this one."

Light rain was expected to begin in parts of Los Angeles County after midnight Friday morning, continuing through much of the day. Runoff and minor flooding from the storm may occur, forecasters said.

Although the rain will be light, some areas could get some high winds. A wind advisory will be in place from midnight to noon Friday in the San Gabriel Mountains and Antelope Valley foothills, where winds are predicted in the 20 to 30 mph range, gusting up to 50 mph.

Conditions in Southern California should dry out on Sunday and Monday, but forecasters said another potentially strong storm could hit the area by Tuesday.

The Associated Press, City News Service and Bay City News Service contributed to this report.