California lashed by deadly 'atmospheric river' storm

At least two fatalities have been reported since Wednesday.

The deadly storm was powered by two overlapping phenomena - an immense airborne stream of dense moisture from the ocean called an atmospheric river, and a sprawling, hurricane-force low-pressure system known as a bomb cyclone.

The blast of extreme winter weather marked the third and strongest atmospheric river to strike California since early last week, with at least two more back-to-back storms forecast over the next several days.

The San Francisco Bay area, the state capital Sacramento and surrounding region were still recovering from flood damage, including levee breaches along the Cosumnes River, when the new bout of showers hit.

The National Weather Service (NWS) predicted rainfall of 1 inch (2.5 cm) per hour, with snow in the Sierra Nevada Mountains and Southern California's coastal ranges falling at the rate of 3 inches (7.6 cm) an hour, making road travel treacherous.

The NWS also warned of likely flash floods and mudslides, especially in places still saturated from previous storms and areas with fire-ravaged hillsides stripped of vegetation from past wildfires.

High-wind advisories and gale warnings were posted up and down the state, as uprooted trees, already weakened by drought and poorly anchored in rain-soaked soil, knocked down power lines and blocked roadways.

Hazardous surf warnings were in effect for the state's three northernmost coastal counties - Mendocino, Humboldt and Del Norte - where three-story waves pounded the shoreline and crashed over beaches.

Human toll

Authorities have reported at least two weather-related deaths from the latest storm. A tree that crashed onto a home overnight killed a 1-year-old baby boy, and a 19-year-old woman died when her car skidded off a partially flooded road into a utility pole on Wednesday.

Four other deaths have been attributed to the New Year's weekend storm that swept northern California - three flood victims found in or near their cars and an elderly man found dead under a fallen tree.

As many as 180,000 homes and businesses, mostly in northern and central California, were without power early on Thursday, according to data by Poweroutage.us.

The region's main utility, Pacific Gas and Electric Company, reported wind gusts topping 100 mph (160 km) and more than 5 inches of rain in some areas.

"This was one of the most powerful winter storms to hit our region in years," PG&E spokesperson Megan McFarland said in an email to Reuters.

Flooding, fallen trees and power lines left major roadways impassable in Point Arena and Gualala, two small Mendocino County coastal communities about 125 miles (201.17 km) north of San Francisco, which have experienced blackouts since Wednesday.

Big River Beach, a picturesque and popular destination for tourists and locals alike about 35 miles farther north in the village of Mendocino, was almost unrecognizable with uprooted trees and debris scattered across mounds of sand awash in pools of standing water.

A short drive farther up the coast at Noyo Harbor in Fort Bragg, professional urchin diver Grant Downie said he moved his boat out of the water ahead of the storm as a precaution.

"The boat, insured or not, I feel safer with it on the truck getting hit by a tree than sinking in the water," he said.

Climate emergency

For Californians, the latest series of storms vividly illustrated the consequences of warmer sea and air temperatures wrought by climate change, producing atmospheric river storms with increasing frequency and intensity in the midst of extreme, multi-year drought.

Governor Gavin Newsom declared a state of emergency on Wednesday, and state officials urged Californians to avoid travel.

Crews in San Francisco spent the night cleaning up debris from felled trees that blocked roadways. The city's fire department rescued a family trapped when a tree fell across their car.

Authorities advised Sonoma County residents near the Russian River between the wine country towns of Healdsburg and Jenner to evacuate their homes as the rain-swollen waterway neared flood stage.

Evacuation warnings were also issued in oceanside towns such as Santa Cruz. Officials shut down a 55-mile stretch of Route 1, a scenic coastal highway, due to flooding and debris. In Santa Barbara County, homes were ordered evacuated in three areas where hill slopes were left denuded by wildfires.