Storm generates rare tornado warning in San Francisco, part of San ...

A storm and wind gusts of up to 60 mph (96 kph) prompted the first tornado warning in San Francisco and caused some damage in the Bay Area on Saturday. Parts of neighboring San Mateo County were also included in the warning to about 1 million people in the area.

The National Weather Service initially sent a Tornado Warning at around 5:56 a.m. for northern San Mateo County and portions of downtown San Francisco. It was lifted by 6:15 a.m. Radar detected possible tornado conditions near San Francisco, South San Francisco, and Pacifica around 5:55 a.m.

The storm toppled some trees onto cars and streets and damaged some roofs in San Francisco, which has not seen a tornado since 2005, according to the Weather Service. The damage was being assessed to determine if there was indeed a tornado.

“This was the first ever warning for a possible tornado in San Francisco. I would guess there wasn’t a clear signature on radar for a warning in 2005,” said Roger Gass, a meteorologist in the Weather Service’s Monterey, California. He said he was not there in 2005.

The fast-moving storm prompted warnings for residents to take shelter, but few people have basements in the area.

“The biggest thing that we tell people in the city is to put as many walls between you and the outside as possible,” Meteorologist Dalton Behringer said.

And in Nevada, up to 3 feet (91 centimeters) of snow was forecast for Sierra Nevada mountaintops, with a winter storm warning in effect through 10 p.m. More than a foot fell at some Lake Tahoe ski resorts, according to the National Weather Service’s Reno office.

Interstate 80 was closed for about an 80-mile (130-kilometer) stretch from Applegate, California, to the Nevada state line just west of Reno, where rain was falling and a winter weather advisory remained in effect through the afternoon.

The agency also reminds everyone of possible flash flooding due to torrential rains. Everyone is encouraged to stay vigilant and aware of weather conditions.

The Associated Press contributed to the report.