Atmospheric River Pummels Walnut Creek; More Rain Coming

WALNUT CREEK, CA — Walnut Creek and the Bay Area were battening down the hatches as a severe storm caused by an atmospheric river slammed the region. The storm brought widespread flooding, thunder, lightning, power outages and winds of up to 60 mph in higher terrains.

As of Tuesday afternoon, the worst of the storm appeared to have passed, at least for the day. The National Weather Service downgraded the storm from a “Level 3” to a “Level 1” on the Storm Impact Scale, and at around 12:30 p.m. the National Weather Service began canceling flood advisories that were issued throughout most of the area early Tuesday morning.

In Walnut Creek, the weather was 52 degrees and cloudy as of 5:15 p.m., following nearly 2 inches of rain in 24 hours, according to the National Oceanic and Atmospheric Administration. AccuWeather reported 3 hours of rain Tuesday in Walnut Creek.

Rain is expected to start up again Wednesday night, and continue through New Year’s Eve.

On Saturday, 0.82 inches of rain is predicted in Walnut Creek, and wind gusts could reach up to 35 mph. The first day of 2023 is forecast to be sunny and 59 degrees, but even more rain is predicted all of next week.

The NWS said Monday that its latest five and seven-day forecasts signal what could be the wettest end of the year in the Bay Area and northern Central Coast since 2005. The largest rain totals have been reported in the North Bay.

By early Tuesday, the National Weather Service reported that Mt. Tamalpais had already received 4.10 inches of rain. As of Tuesday at noon, Kentfield reported a 24-hour total of 4.65 inches, while Mill Valley reported 2.56 inches, according to the National Oceanic and Atmospheric Administration.

Just south of the Golden Gate Bridge, San Francisco recorded 1.86 inches; Oakland recorded 2.41 inches; Mt Diablo recorded 2 inches; and San Jose International Airport recorded 0.68 inches. Further south along the coast, Ben Lomond recorded 4.46 inches, and Soquel recorded 3.11 inches.

SFO Airport reported gusts as high as 47 mph, and gusts of up to 60 mph were reported in higher terrains.

The storm left widespread flooding and chaos in its wake. PG&E said that 6,800 customers across the Bay Area reported power outages by 9 a.m. Tuesday. Flooding was reported near Santa Rosa, Napa, Redwood City, and Oakland, as well as on the 101, I-580, and on Highway 1 in San Mateo County, in addition to many other incidents. The California Highway Patrol said it was responding to more than 60 incidents on Bay Area freeways Tuesday morning, and BART trains were delayed by up to 20 minutes.

Early Tuesday morning in San Ramon, intense rain caused the roof of a Big 5 Sporting Goods store to collapse. No one was injured, but surrounding stores are closed as officials inspect their structural integrity.

In Lamorinda, Moraga Road was closed mid-day Tuesday between Moraga and Lafayette after a large tree fell on a power line.

Anyone in unincorporated Contra Costa County can pick up sandbags at any of six locations around the county.

Do you have stories or photos from the rain? Email maggie.fusek@patch.com.