The rain that will continue to soak the Bay Area this week left two people dead Thursday after they were found inside a submerged car in Millbrae, leading authorities to restate warnings about hazardous driving conditions and flooding in low-lying and poor drainage areas over the holidays.
Snow storms inundated the Sierra Nevada region, and the weather service continued to discourage mountain travel this weekend due to reduced visibility, travel delays and possible white-out conditions with at least four more feet of snow still to come.
On Thursday morning, two people were found dead inside a vehicle submerged in a flooded underpass in Millbrae. Authorities said another person who was trapped on top of their own flooded car had called for help. Rescuers spotted the second car submerged in the water.
Officials reminded drivers to exercise extreme caution when they encounter flooded roadways: “If you see standing water, and if you’re not sure of the depth, don’t attempt to cross it,” said San Mateo County Sheriff’s Detective Javier Acosta. “It’s not worth it.”
The wet weather continued after a low-pressure system traveled from British Columbia to the coast near the Oregon-California border earlier this week and started pushing moisture into the area, according to the weather service.
Thursday’s storm began tapering off over much of the region by early afternoon. But another system was expected to move in Friday evening and last into Saturday afternoon, making a rainy Christmas Eve and Christmas morning likely. More rain was expected Sunday through Thursday of next week.
Showers were expected to be “fairly uniform” across the Bay Area, with another half an inch or so of precipitation expected across the region through Thursday night, according to NWS forecaster Sean Miller. There will be a chance for as much as 1 inch of rain on Friday, with half an inch or less next week between Tuesday and Thursday.
Lower elevations in the Bay Area, including in the South Bay, East Bay and interior San Francisco Bay, may get a total of 1 to 3 inches of rain this week. The Santa Cruz Mountains and North Bay mountains were expected to receive 5 to 6 inches of rain, while the North Bay valleys could get between 2 and 3½ inches of rain.
As of 1:25 p.m. Thursday, 48-hour rainfall totals included: 4.41 inches at Scott Creek, 4.17 inches at Mount Diablo, 3.34 inches in Kentfield, 3.27 inches at Mill Valley at Mount Tamalpais, 3.04 inches at the Ben Lomond landfill, 2.87 inches at the San Francisco International Airport, 2.41 inches at the Oakland International Airport, 1.48 inches in Redwood City, and 0.43 inches at the San Jose International Airport.
Temperatures should be milder through the weekend, with highs from the 50s to the low 60s and lows in the upper 40s to around 50 degrees. Wind gusts could reach 25 to 35 miles per hour in the hills and higher peaks.
There were reports of roadway flooding in coastal areas in San Mateo County. Cal Fire CZU posted video Thursday morning of flooding in an El Granada neighborhood, in which officials were knee-deep in water. A large tree blocked traffic in all lanes of northbound Highway 13 in Oakland shortly after 7 a.m. And a mudslide was reported on Westover Drive in the Oakland Hills.
Pretty good-sized mudslide on Westover Drive in the Oakland hills. Appears to be on a double lot where the home has been under construction for quite some time. Maybe time to abandon the project? @OakTribNews @EastBayTimes pic.twitter.com/QF3k6MRSFK
— Tyska (@Tyska) December 23, 2021
The Sierra Nevada was expected to receive at least 4 to 5 more feet of snow through through the weekend, with up to 9 feet in elevations over 8,000 feet, according to the weather service. Throughout the week, Echo Pass was expected to get 48 to 60 inches of snow, Tioga Pass was forecast to receive 24 to 36 inches, and Donner Pass, Caron Pass, Ebbetts Pass and Sonora Pass could get 80 to 100 inches.
As of Thursday morning, 24-hour snow totals included 9 inches at Sugar Bowl and Kirkwood, 8 inches at Northstar and Heavenly, and 6 inches at Palisades Tahoe and Donner Summit.
The snow storm was expected to lighten up by Friday afternoon before ramping up again Friday night into Saturday. The snowfall could weaken Sunday night, with additional chances of snow through next Thursday.
As of Thursday, chains were required on Highway 50 and Interstate 80 for all vehicles, except those with four-wheel-drive and snow tires, according to Caltrans.
“Everything you can think of with hazardous mountain travel with feet of snow, it’s probably happening,” said NWS forecaster Emily Heller.
The strongest winds were expected to hit the Lake Tahoe region through Saturday night, with gusts between 40 to 50 miles per hour over the mountains that could lead to a reduction in visibility in combination with the falling snow.
“Anyone traveling this holiday over the mountains needs to be prepared for winter-driving conditions, have warm clothes, extra food and water, chains and be prepared to be turned around in case the roads close,” Heller said. “You should have an emergency kit in your vehicle in case you get stuck.”
The majority of the Golden State has been overtaken by “extreme drought” after two dry winters in a row, but some of that has been alleviated by recent atmospheric river storms.
As of Wednesday, San Jose has received 5.07 inches of rain since the water year began on Oct. 1, compared to 0.87 of an inch of rain the city got in that same time period last year, according to the weather service. San Jose’s rainfall total is 147 percent of historic averages from 1991 to 2020, while the city was 25 percent of normal this time last year.
“Getting repeated rainfall is definitely something that is beneficial for us,” Miller said. “There are two types of drought — short-term and long-term. When we get events like these, they’re helpful at alleviating short-term drought, but it takes more over a longer period of time to alleviate the long-term drought we’re in.”
The storm earlier this month also bolstered California’s statewide snowpack from 19 percent of historic averages on Dec. 10 to 91 percent of historic averages as of Wednesday, according to the National Weather Service’s California Nevada River Forecast Center.
“With all of the snow, that’s going to also increase our snow pack, which helps in the spring and summer months with run-off, so that’s beneficial as well,” Heller said. “With long-term precipitation, it’s hard to say, because it takes multiple years sometimes to get yourself out of a drought.”