First-ever tornado warning shocks San Francisco residents during intense storm
San Francisco residents were woken up by a tornado warning early Saturday morning during a powerful storm system that battered the region with heavy rain and wind.
It was the first-ever tornado warning for San Francisco, but not the first tornado, cited CBS News Bay Area meteorologist Paul Heggen.
The National Weather Service issued the warning for northern San Mateo County and parts of downtown San Francisco, just before 6 a.m. until 6:15 a.m.
According to the NWS, there was a cyclonic signature on the radar that had produced enough rotation signature to prompt the warning.
"The radar scan at 5:52am clearly shows a "hook echo" offshore — that's the signature we look for to identify a developing tornado. This feature was embedded within a broad area of very heavy rain, but it still stands out," Heggen explained.
The NWS Bay Area said the warning was over for San Francisco at 6:07 a.m. And let the tornado warning expire at 6:15 a.m.
The warning led to a flurry of social media posts from residents who were woken up by the alert on their cell phones. It was being reported as the first-ever tornado warning issued for San Francisco.
There was also a special alert issued for a possible water spout on San Francisco Bay in the area of the Bay Bridge that expired ten minutes after the tornado warning.
While the strongest part of the system has passed, isolated severe thunderstorms remain possible for parts of the Bay Area through the morning, the National Weather Service said.
According to PG&E, the storm conditions caused power outages for thousands of people in the Bay Area.
The tornado warning in San Francisco was just the first of multiple extreme wind events connected to the powerful storm that passed through Northern California overnight and continued to cause problems Saturday.
High winds were causing impacts across the region, including a city-wide power outage in the North Bay city of Novato and a full closure of Interstate 580 in both directions at the San Joaquin and Alameda county line after a multiple-vehicle collision involving a big rig due to high winds.
On Saturday afternoon, a tornado touched down in the Santa Cruz County town of Scotts Valley. Police had initially issued an alert regarding a multi-vehicle accident, but later reported that witnesses said a tornado had touched down on Mount Hermon Drive, throwing "multiple cars off the road."
The Bay Area office of the National Weather Service later confirmed that a tornado had occurred based on "video, photos, firsthand accounts, and radar signatures"
