Atmospheric river brings heavy rain and snow to NorCal, prompts evacuations in 2 counties

A powerful storm packing heavy rain, snow and wind pounded parts of California and western Nevada on Wednesday, toppling trees, and causing power outages and mud flows in vast areas scarred by wildfires.

The onslaught was being fueled by a potent atmospheric river from the Pacific Ocean that punched into the state through the San Francisco Bay Area overnight, drifted down the coast past Santa Cruz and stalled over Big Sur before pivoting back northward.

Tens of thousands of utility customers lost power in the San Francisco and Sacramento areas, and a wind gust hit 125 mph (201 kph) at Alpine Meadows near Lake Tahoe.

Mudslides near Salinas south of the Bay Area caused “mild to moderate” damage to about two dozen rural ranch homes beneath hillsides scorched by the River Fire last August, said Dorothy Priolo with the Monterey County Regional Fire Protection District.

One woman was treated for broken bones after mud went “completely through the house” in the early morning hours, Priolo said. Fifty horses were rescued.

“We are expecting there could be more earth movement here in the next couple of days,” Priolo said.

Evacuation orders were issued in advance in Santa Cruz and San Mateo counties around an area scorched by wildfires ignited by lightning last August. The state also positioned teams with specialized rescue skills in five counties.

Santa Cruz County initially appeared to dodge trouble, with no debris flows reported overnight. But the weather service said the atmospheric river’s afternoon pivot renewed risks of flash floods from burn scars in that region.

On the far north coast, three motorists stranded in snow late Tuesday were rescued by Humboldt County sheriff’s deputies who made their way through several miles of treacherous conditions while clearing dozens of downed trees and powerlines. The motorists were uninjured when they were located about 3 a.m. Wednesday.

Rare snow was reported in Sonoma and Napa counties north of San Francisco at elevations as low as 1,300 feet (396 meters). Low-level snow also fell in the northern Sacramento Valley, closing Interstate 5 in Shasta and Siskiyou counties.

About 500 miles to the south, deteriorating conditions intermittently closed I-5 in Tejon Pass between Los Angeles and the southern San Joaquin Valley.

The National Weather Service issued a rare blizzard warning for Lake Tahoe and much of the Sierra in California and Nevada, forecasting up to 6 feet (2 meters) of snow on upper elevations and winds in excess of 100 mph (160 kph) over ridgetops.

More than a foot of snow was reported early Wednesday in the foothills north of Reno. The Mount Rose ski resort on the southwest edge of town announced it would be closed “due to blizzard conditions and high winds.”

“The first phase of this impressive and hazardous storm is currently driving atmospheric river moisture and heavy snow across the northern Sierra and western Nevada,” the National Weather Service in Reno said.

By early afternoon, the storm had dumped 42 inches (106 centimeters) of snow on the summit of Mammoth Mountain, the resort reported.

A 75-mile (120-kilometer) stretch of U.S. Highway 395 south of the California-Nevada line was shut down and chains or snow tires were required on all mountain passes in the central and northern Sierra, including a stretch of Interstate 80 north of Lake Tahoe.

Nevada Gov. Steve Sisolak ordered a two-hour delay for state workers to report to work.

The Washoe County School District notified parents Tuesday night that all Nevada public schools in Reno-Sparks and the north Lake Tahoe area would be closed Wednesday.

A warning was also issued for widespread high avalanche danger on the eastern slopes of the Sierra because of heavy snow combining with wind through Friday morning.

The storm was expected to drop down into Southern California on Thursday, bringing several inches of rain and concerns over burn areas, as well as several feet of snow to high elevations of the region’s mountains.

The atmospheric river is 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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