‘A Big Drop in the Bucket’: After Drenching Northern California, Massive Storm Heads South

A massive storm barreled toward Southern California on Monday after flooding highways, toppling trees, cutting power to about 380,000 utility customers and causing rockslides and mudflows in areas burned bare by wildfires across the northern half of the state.

Drenching rains and strong winds accompanied the weekend arrival of an atmospheric river — a long plume of Pacific moisture — into the drought-stricken state.

Rainfall records were shattered and heavy snow pounded high elevations of the Sierra Nevada. The National Weather Service issued numerous flash flood warnings.

There were widespread power outages in Northern California, with Pacific Gas & Electric reporting Sunday evening that about 130,000 customers did not have electricity, though the utility said power had been restored to about 250,000 customers.

“What’s most interesting about the storm is that we typically tend to get stronger storms into the winter,” said Sean Miller, a meteorologist with the National Weather Service. “This early in the season is anomalous and the moisture was like a firehose in our area.”

Miller advised Bay Area residents traveling today in the wake of the massive storm to be cautious and take proactive measures to clean out storm drains and gutters. “Trees have been weakened by wind and water,” he said. “Behind the system, the surf is really high and strong. There will be some big waves for the next few days, and it will take time for the swells to go down.”

Flooding was reported across the San Francisco Bay Area, closing streets in Berkeley, inundating Oakland’s Bay Bridge toll plaza and overflowing rivers in Napa and Sonoma counties.

Sacramento received 5.4 inches of rain, smashing the all-time one-day rainfall record dating back to 1880, the weather service said. Interstate 80, the major highway through the Sierra to Reno, Nevada, was shut down by heavy snow early Monday.

The same storm system also slammed Oregon and Washington, causing power outages that affected tens of thousands of people. Two people were killed when a tree fell on a vehicle in the greater Seattle area.

In California’s Colusa and Yolo counties, state highways 16 and 20 were shut for several miles because of mudslides, the state Department of Transportation said.

South of San Francisco, evacuation orders were in effect in the Santa Cruz Mountains over concerns that several inches of rain could trigger debris flows in the CZU Lightning Complex Fire burn scar when the storm moved through early Monday.

Further south, evacuation warnings for parts of western Santa Barbara County were upgraded to evacuation orders in the area burned by this month’s Alisal Fire.

Officials said mountain areas above 9,000 feet in the Sierra Nevada could get 18 inches of snow or more from Sunday until Monday morning.

Recent storms have helped contain some of the nation’s largest wildfires this year. But it remains to be seen whether the wet weather will make a dent in the drought that’s plaguing California and the western United States.

"This was a big drop in the bucket, but at the same time, it's a big bucket," said Alison Bridger, chair of the Department of Meteorology and Climate Science at San José State University.  "We're talking about the whole West being dry, and only a part of the West got hit by this storm, certainly in the Northern California foothills and higher areas that drain down into our reservoirs. This is going to help."

California’s climate is hotter and drier now, and that means the rain and snow that does fall is more likely to evaporate and less likely to absorb into the soil.

California’s 2021 water year, which ended Sept. 30, was the second-driest on record and last year’s was the fifth-driest on record. Some of the state’s most important reservoirs are at record low levels.

“If you are in the vicinity of a recent burn scar and haven’t already, prepare now for likely debris flows,” the Sacramento weather service tweeted. “If you are told to evacuate by local officials, or you feel threatened, do not hesitate to do so. If it is too late to evacuate, get to higher ground.”

South of San Francisco, evacuation orders were in effect in the Santa Cruz Mountains over concerns that several inches of rain could trigger debris flows in the CZU Lightning Complex Fire burn scar when the storm moves through early Monday.

"We've seen a lot of drought and wildfires in recent years, but we kind of forget about the fact we've also seen some conspicuously extreme weather events as well in that same period," said Daniel Swain, a climate scientist at UCLA and The Nature Conservancy. "This is somewhat characteristic of what we expect to see in California's warming climate, where the overall amount of precipitation may not change tremendously."

This post includes additional reporting from KQED's Spencer Whitney and Natalia Navarro, as well as The Associated Press.