Powerful storm slams into California, bringing power outages and fears of flooding

Updated January 5, 2023 at 5:05 a.m. ET

Heavy rainstorms rolled into California early Thursday, bringing strong winds, heavy rain, snow and power outages as residents braced for possible flooding.

It is the third time an atmospheric river has hit the state since December 26.

“We anticipate this could be one of the most challenging and impactful series of storms to hit California in the last five years,” said Nancy Ward, the new director of the California Governor’s Office of Emergency Services. on a late morning. press conference about the threat.

Gov. Gavin Newsom signed a statewide emergency declaration Wednesday to help agencies send aid and resources to where they are needed, Ward said.

As the system arrived, many areas will also face the effects of a bomb cyclone: ​​The powerful system was seen “undergoing bombogenesis” off the northern coast of California, the NWS office in Sacramento said, referring to the rapid intensification of a cyclone with medium width.

Forecasters have been raising the alarm about the storm for days now, saying it could start making landfall as early as Tuesday evening.

As of 4 a.m. ET Thursday, the band of rain had descended on the Los Angeles area and was “moving faster than expected,” which could be a good thing, since fewer people will be on the roads and rainfall totals may be less than previously forecast, the NWS office in Los Angeles said.

Rainfall is forecast to reach 2 to 4 inches on the coast, valleys and deserts, while the mountains could get up to 10 inches of rain, with heavy snow at higher elevations. Forecasters are urging people to take extra care in areas where wildfires have recently burned through vegetation, citing the increased risk of flooding and landslides.

The large system prompts warnings along the Pacific coast

Weather experts warned people in their coverage areas to prepare for possible power outages and that travel could be threatened by strong winds, debris and downed trees and power lines.

As of 4 a.m. ET Thursday, nearly 196,000 Californians were without power, according to Poweroutage.us.

In an area stretching hundreds of miles along the coast, National Weather Service offices from Los Angeles to Eureka, Calif., and Medford and Portland, Ore., warned people of the threat of damaging winds, with high gusts expected to reach to 60 and 70 mph in some areas, and even exceeds 100 mph in parts of the Bay Area.

“The most intense part of this weather event will occur later this evening and last through midday Thursday,” the NWS office in Los Angeles said. “A slow-moving cold front will absorb moisture from a mean atmospheric river.”

Atmospheric rivers carry tremendous amounts of water

Atmospheric rivers are a normal part of the West Coast weather pattern, and they are often the solution to dry months of warm weather, bringing much-needed rain and snowfall that piles water up in the mountains.

Rainfall can be extreme: A single atmospheric river “can hold more water than the Mississippi River at its mouth,” as NPR has reported. Forecasters have long warned that wind systems are very dangerous. In 2017, one of the storms felled the legendary “Pioneer Cabin Tree” sequence in Calaveras Big Trees State Park.

“It’s just a narrow area of ​​high moisture that gets transported away from the tropics to higher latitudes,” often before a cold front arrives, NWS senior forecaster Bob Oravec recently told NPR.

For states along the West Coast, atmospheric rivers are “actually responsible for a good majority of the precipitation during the coldest season, which is the season when they get most of the rain,” Oravec said.

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