SAN JOSE, Calif. — Even experienced weather experts were stunned by the destructive, deadly and ultimately rare “bomb cyclone” that touched down in the region Tuesday afternoon.
“Even by the standards of what has turned out to be one of our most extraordinary winter seasons in a very long time, (Tuesday) stands out,” National Weather Service meteorologist Warren Blier wrote in the agency’s Area Forecast Discussion early Wednesday morning.
While it rained throughout the Bay Area for most of Tuesday, it was the explosive and violent wind that packed a real punch, tearing down trees, toppling big rigs and roiling the waters with gusts of more than of 81 miles per hour, according to the NWS.
“I’m a scientist. I tend to not be a fan of flamboyant adjectives,” Blier told Bay Area News Group in a phone interview Wednesday morning. “But after the winter we’ve had, to get something like yesterday, I thought it was extraordinary.”
By 6 a.m. Wednesday morning, the winds had mostly calmed to a constant 12 mph in San Jose, and they were forecast by the NWS to drop even further as the lingering storm dissipated. But after the remarkable storm heads out, the impacts will continue to be felt.
The violent whipping winds left at least two people dead in the Bay Area, both killed by toppling trees landing on vehicles, and caused massive traffic jams like on the Bay Bridge in which a big rig truck toppled over, blocking most eastbound lanes for hours Tuesday night
An untold number of trees were ripped out of saturated soils at the roots or had major limbs pulled down amid the winds. In turn, many of those broken or dead trees were responsible for power outages that lasted into Wednesday.
Pacific Gas and Electric Company reported that 177,000 Bay Area customers were without power as of 9:30 p.m. Tuesday. That number was as high as 244,000 customers at 6:45 p.m.
On top of the wind, high rain levels left pools of standing water throughout the region with significant rain. 24-hour rain totals as of 7:46 a.m. Wednesday included 0.89 inches in San Jose, 1.24 inches in downtown San Francisco, 1.43 inches in Oakland, 1.06 in Walnut Creek, 1.96 inches in Redwood City and 1.29 inches in Hayward.
The bomb cyclone storm was created by an atypically low pressure system, according to the NWS.
“The thing that’s really extraordinary meteorologically, is to have that deep a low pressure system off the coast of San Francisco,” Blier said. “It would be accurate to say ‘explosively developed’ meets the criteria.”
Blier said the storm was “once in every 10 years or rarer,” but acknowledged that the storm’s unique nature could be lost among the myriad other rare weather events of a wildly active winter season in the Bay Area.
“But when you talk the New Year’s Eve storm, the flooding or even the winds that occurred just recently … they were all remarkable,” Blier said. “There was so much that had already happened this winter season and then this on top of it. Any other season, this would be the extraordinary, memorable event. Now, this is like, top five.”
On Wednesday, rain was expected to remain in the area during the morning hours, but totals weren’t forecast to match the Tuesday rainfall. In San Francisco, San Jose, Oakland and Walnut Creek, less than one-tenth of an inch of rain was predicted. On the coast in places like Santa Cruz and Half Moon Bay, between one-tenth and one-quarter of an inch was expected.