Violent storms are causing problems in and around San Francisco

An ice storm hit Iowa and eastern Nebraska over the weekend, shutting down a major highway as cars and trucks veered off the road. At least one person was killed in an accident on icy roads in Nebraska.

The National Weather Service in Des Moines issued a dense fog warning Saturday that was expected to remain in effect until 11 a.m. CT Sunday. Dense fog spread across much of the state, reducing visibility to a quarter mile or less in some places, the weather service said. By Saturday evening, most of the ice had turned to freezing rain, but roads in eastern Iowa were still at least partially covered in ice or snow, forecasters said.

⚠️Attention Sunday Morning Travelers – Areas of dense fog and visibility of less than 1/4 mile at times will continue this morning. Allow a little extra time and distance if you head out this morning! #iawx @iowadot pic.twitter.com/twUvXWPrb0

— NWS Des Moines (@NWSDesMoines) December 15, 2024

Authorities say one person died while driving on icy roads in eastern Nebraska. The Washington County Sheriff’s Office said a 57-year-old woman was killed in a crash after she lost control of her pickup truck and struck an oncoming truck on Highway 30 near Arlington. The other driver suffered minor injuries in the accident. Washington County is located near Nebraska’s eastern border with Iowa, near Omaha.

Roads in that area were smooth enough Saturday to play hockey in the street, one person was seen in a social media video reposted by the National Weather Service in Omaha. A dense fog warning was also in effect for the region until 11 a.m. CT Sunday.

“Dense fog continues to develop in our area and is expected to persist into tomorrow morning,” the National Weather Service in Omaha wrote in a statement Saturday evening. “As visibility is below a quarter of a mile at times and slippery patches are forming again on some roads, please exercise caution and take it slowly when traveling!”

Meteorologists warned that untreated roads could refreeze overnight as temperatures drop.

3:10 am | The next wave of precipitation is moving through southeast Nebraska. The good news is that the freezing line has moved northward in the last few hours. We are watching temperatures closely as this rain sets in, but we could see more freezing rain, especially north of I-80. pic.twitter.com/xlB7K32y3l

– NWS Omaha (@NWSOmaha) December 14, 2024

Many events across the region were canceled as the storm hit Friday evening, and businesses announced plans to open late Saturday as authorities urged people to stay home if possible. However, temperatures rose so much in the afternoon that the ice melted in most places.

“Fortunately, some warmer air is getting in behind it, so it’s temporary,” said Dave Cousins, a meteorologist at the National Weather Service office in Davenport, Iowa.

Elsewhere, a storm and wind gusts of up to 60 miles per hour triggered the first tornado warning in San Francisco and caused some damage. Parts of neighboring San Mateo County were also affected by the warning, which was issued to about 1 million people at 5:51 a.m. and was lifted about 20 minutes later.

Later on Saturday, a Tornado touched down near a shopping center In Scotts Valley, near the city of Santa Cruz, about 70 miles south of San Francisco, there were overturned cars and downed trees and utility poles, according to the National Weather Service.

“Based on video, photos, first-hand reports and radar signatures, a tornado occurred at 1:40 p.m. PT,” the service said, adding that a team will investigate and rank it.

Images uploaded to social media showed at least three vehicles lying on their hoods or on their sides, their windshields shattered and trees and power lines lying on the ground.

Several people were injured and taken to hospitals, Scotts Valley police said.

“The tornado caused significant damage in several areas, including the overturning of several vehicles in and around the Mt. Hermon Drive shopping district,” the agency said in a statement. It urged people to avoid the area.

One of the injured was a battalion chief with the California Department of Forestry and Fire Protection, KSBW-TV reported.

In San Francisco, some trees fell on cars and streets and damaged roofs. According to the weather service, the city has not experienced a tornado since 2005. The damage was assessed to determine whether the city was actually hit by a tornado.

“This was the first warning of a possible tornado in San Francisco. “I suspect there was no clear indication of a warning on the radar in 2005,” said Roger Gass, a meteorologist with the weather service in Monterey, California. He said he wasn’t there in 2005.

Due to the fast-moving storm, residents were urged to seek shelter, but few people in the area have basements.

“The biggest thing we tell people in the city is to put up as many walls as possible between ourselves and the outside world,” said meteorologist Dalton Behringer.

In northern New York state, people dug out after heavy snow fell. More than 33 inches were reported near Orchard Park, where residents are dealing with lake-effect snow this time of year.

And in Nevada, up to 3 feet of snow was predicted on the Sierra Nevada mountain peaks. More than a foot fell at some Lake Tahoe ski resorts, and a wind gust of 112 mph was recorded at Mammoth Mountain Resort south of Yosemite National Park, according to the National Weather Service’s Reno office.

A winter storm warning was set to expire at 10 p.m. PT Saturday, but an avalanche warning remained in effect for elevations above 8,000 feet around Tahoe into the following night.

Interstate 80 was closed for an 80-mile stretch from Applegate, California, to the Nevada line west of Reno, where it was raining and a winter weather advisory was in effect throughout the afternoon. The California Highway Patrol reopened the road in the afternoon to passenger vehicles with chain or four-wheel drive and snow tires, but it remained closed to semi-trucks.

In western Washington, tens of thousands of people lost power Saturday, local news outlets reported, as a system brought rain and gusty winds.