The Bay Area’s second “atmospheric river” storm of the winter announced its presence Saturday with intense power, unleashing a torrent of rain that closed freeways, trapped drivers, flooded streets and broke records while heavy winds uprooted trees throughout the region.
The National Weather Service said 5.46 inches of measured rain fell in downtown San Francisco between midnight and 8 p.m., making it the second-largest day of rainfall ever in that city. According to meteorologist Jan Null, the only day to see more rain in downtown San Francisco was Nov. 5, 1994, when 5.54 inches fell. Saturday’s rain surpassed the 4.67 inches that fell on Jan. 29, 1881.
In downtown Oakland, the 3.69 inches that fell between midnight and 3 p.m. set a mark for the most rain on the final day of a year. The previous mark, set in 2005, was 1.81 inches, according to the weather service. Records have been kept since 1849.
The nonstop rain created chaos throughout the Bay Area, from San Ramon, where police deployed an armored vehicle to help evacuate residents from flooded roads and homes, to Santa Cruz County, where flooding hit downtown Soquel in the early evening.
Alameda County Sheriff’s deputies and fire department personnel rescued 19 elderly patients from a long-term care facility in Castro Valley.
The California Highway Patrol closed Highway 101 in South San Francisco for much of the day because of major flooding and diverted all traffic to Interstate 280. The northbound lanes were reopened around 8 p.m., and southbound lanes were reopened around 9 p.m.
The CHP also closed Interstate 580 in both directions at the 150th Avenue exit because of flooding. Three lanes were closed on westbound I-580 at Eden Canyon Road for two hours after a mudslide.
In the Santa Cruz Mountains, an active slide closed Highway 9 between Bear Creek Road and Riverdale Boulevard. The CHP reported it would take several days to clear the debris.
A large tree fell onto westbound I-580 east of Keller Avenue just after noon and blocked at least two lanes of the freeway.Later, the same thing happened on westbound I-580 at Highway 13 in the East Bay and on southbound I-280 near the Westborough Boulevard exit on the Peninsula.
In Palo Alto, police said Pope Chaucer Bridge was flooded by 11:30 a.m. and told residents to take precautions as the water levels of the San Francisquito Creek rose. That same creek runs past Stanford Shopping Center, the Vi retirement center and the Ronald McDonald House for families of kids under treatment at Stanford hospital.
The El Camino Real underpass at University Avenue also was flooded and not passable, police said. Also closed were Quarry Road between Palo Alto Avenue and El Camino Real; Palo Alto Avenue between Chaucer and Seneca streets; and University Avenue between Middlefield Road and Woodland Avenue.
Alameda Creek near Fremont also had gone above its flood stage levels, according to the weather service. The creek was 4 feet above flood stage before noon and was expected to rise another foot before peaking. The Tice Creek in Walnut Creek also flooded, forcing the closure of Tice Valley Boulevard and trapping one person’s car.
In Pleasant Hill, 88-year-old Patsy Costello was rescued after being trapped in her vehicle for over an hour on Astrid Drive. She had driven her car on the flooded street, thinking she could make it, when it stalled in 2 feet of water. Nurse Katie Leonard, who lives down the block, used her kayak to bring Costello hot tea, blankets, food and a phone to call a friend.
Wind advisories remained in effect throughout the day. Wind gusts whipped up to 63 mph at Loma Prieta in the Santa Cruz Mountains; 60 mph at the Black Diamond Mines in Antioch; 55 mph on the Peninsula; and 50 mph in Livermore.
“It’s what we expected,” NWS meteorologist Ryan Walbrun said of the storm. “We don’t expect it to stall or lose strength. It’s moving steadily.”
The storm was having its most powerful impact in the mountains and hills. By 3 p.m. Saturday, about 8 inches of rain had fallen over a 24-hour period in Ben Lomond in the Santa Cruz Mountains and close to 5 inches fell over the same time on Mount Diablo in Contra Costa County.
Danville received almost 5½ inches of rain over the same period, while 3 ¾ inches dumped at the Oakland and San Francisco airports. A bit more than 3 inches fell in Richmond, and 2 ¾ inches fell in Walnut Creek and Concord.
San Jose received less than a quarter-inch of rain during the 24 hours before noon, while an area near Coyote Creek received barely more than a half-inch. Those areas were hit harder later Saturday.
“The main part of the rain is pretty much over most of the Bay Area, and the areas from Marin, Alameda and Contra Costa (counties) were getting the brunt of it,” Walbrun said Saturday morning. “We expect it to stay that way roughly through noon to 2 p.m., then it will shift more toward the South Bay and the Central Coast.”
Even before then, flooding closed Niles Canyon and mudslides did the same to Morris Canyon east of Canyon Heights. Niles Canyon was expected to be open by 8 p.m., but Morris Canyon might be closed for days, police said. Police also closed Paseo Padre Parkway after power lines collapsed and fell at Olive Avenue.
The CHP shut down Highway 92 between the lower lakes and Main Street in Half Moon Bay from about 10 a.m. to 2 p.m.
All lanes on southbound Highway 17 also were closed near the Alma College Road exit because of flooding, according to the California Highway Patrol. The CHP’s daily log of highway incidents remained above 100 through the morning and early afternoon. Most of the incidents were minor vehicle collisions and traffic hazards caused by the rain.
The Bay Area’s most famous flood-prone river, the Russian River, didn’t get enough rain to flood. And Coyote Creek in San Jose, which flooded in February 2017, causing $100 million damage to downtown San Jose, also was in OK shape throughout the day. It was forecast to peak around 9 p.m. Saturday at 1 foot below its flood stage.
Multiple rockslides shut down Highway 1 from San Luis Obispo County to within 2½ miles of Big Sur in Monterey County. The California Department of Transportation did not have an estimate for when it would reopen.
The weather also made for miserable going on BART. The system endured a major delay about 1:30 p.m. because of trains with mechanical issues and the rain. Flooding forced part of the Montgomery Street station in San Francisco to be closed, and BART also had to stop its Oakland Airport Connector service for about a 15-minute stretch.
The rain will clear out of the region by Sunday, Walbrun said. But the appearance of the sun will be only a brief one, with more light rain expected on Monday before a third atmospheric river storm bears down on the region.
“We’re already watching that one,” Walbrun said.
That third storm is expected to arrive by Wednesday.
Staff writers Paul Rogers, Martha Ross and Julia Prodis Sulek contributed to this report.