<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/TejonPass_CHPFortTejon_112819.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/TejonPass_CHPFortTejon_112819.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/TejonPass_CHPFortTejon_112819.jpg?v=ap&w=980&h=551 800w" > Crews clearing vehicles from the Southern California mountains. (Twitter: @CHPFortTejon)

At a Glance Interstate 5 is closed in Southern California due to heavy snow.

One hundred miles of Interstate 5 in Northern California were closed due to multiple spinouts.

All lanes of the road reopened by Wednesday evening.

A portion of Interstate 80 was also shut down.

Thousands lost power due to high winds. A winter storm is now snarling holiday traffic across southern California after stopping traffic across Northern California.

A portion of Interstate 5 from Grapevine to Castaic, California, through Tejon Pass closed Thursday morning as heavy snow sweeps through the higher elevations. Snow gates were opened on I-5 near Santa Clarita to force northbound cars back southbound and down in elevation. Southbound lanes fully reopened Thursday afternoon. Several other major routes through Southern California are also closed.

The unusually intense winter storm downed trees, knocked out power and closed highways in parts of California Wednesday.

Motorists on Interstate 5 in Northern California reported being stuck on the road for hours and some spent the night in their cars, The Associated Press reported.

<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/I5BackupCalTrans.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/I5BackupCalTrans.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/I5BackupCalTrans.jpg?v=ap&w=980&h=551 800w" > The California Department of Transportation and California Highway Patrol work to reopen a stretch of Interstate 5 in the northern part of the state on Wednesday, Nov. 27. 2019, after a winter storm caused multiple motor vehicle accidents and traffic backups. (Caltrans District 2 via Twitter)

Christina Williams of Portland, Oregon, told the AP that it took her and her 13-year-son 17 hours to reach Redding, California, a journey that would normally take 10 hours.

Williams told the AP she and other stranded drivers used weather-related hashtags to connect on the social media platform Twitter and share information on road conditions. Williams described “spin-outs everywhere” and abandoned trucks.

"There were spin-outs everywhere, there were trucks that were abandoned and every time we stopped and started moving again, there were people who couldn't start moving again," she said. "Every time we stopped I was like, is this it? Are we going to be here overnight?"

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About 100 miles of Interstate 5 between Yreka and Redding near the Oregon border was closed Tuesday night and into early Wednesday morning due to multiple vehicle spinouts , according to the California Department of Transportation. The southbound lanes reopened Wednesday morning. The northbound lanes reopened heading from Redding, California, all the way to the Oregon border Wednesday evening.

Authorities were working to remove "the extremely large number of vehicles" off the road.

"Those vehicles must be removed in order to get traffic flowing normally and the road plowed," Caltrans tweeted earlier in the day.

The southbound portion of the interstate was also shut down from Ashland, Oregon, due to the conditions in Northern California , but has reopened.

The westbound lanes of Interstate 80 between Truckee and Nyack were also closed Wednesday morning due to multiple spinouts, the California Highway Patrol said. The roadway later reopened to passenger vehicles only.

The Placer County Sheriff's Office posted video of whiteout conditions in North Lake Tahoe.

Several other state highways in Northern California were closed or down to one lane overnight and into Wednesday morning due to snow, ice or trees blocking the roadway, Caltrans said. Highway 20 in Nevada County was closed near the intersection of I-80 due to whiteout conditions and excessive snow, and Highway 49 was closed between Downieville and Sattley in Sierra County.

Winter storm warnings were in effect across much of the region. The National Weather Service in Sacramento said travel was highly discouraged . The NWS advised travelers to be prepared for major delays and near-whiteout conditions in some areas. The worst impacts were expected today across the northern Sierra Nevada.

"The timing is unfortunate for holiday travel because it's going to have a lot of wintry impacts ," Kevin Durphee, a meteorologist with the National Weather Service, told KFSN-TV.

The NWS in Eureka warned that rain and hail were making roads slippery.

More than 76,000 homes and businesses were without power in California Wednesday morning, according to PowerOutage.us. Many of the outages were caused by high winds.

The storm met the criteria for a bomb cyclone as it moved toward the coasts of Northern California and southern Oregon on Tuesday, meaning its pressure dropped rapidly. The Weather Channel has named the system Winter Storm Ezekiel.

The storm's impacts started Tuesday and continued overnight, with snow, rain and heavy winds.

Authorities asked travelers to practice care when driving and check road conditions before heading out.

"There's going to be a lot of extra vehicles on the roadway," Shasta Tollefson with the California Highway Patrol told KFSN. "Give yourself plenty of time when you are heading out the door, and if you have a normal four-hour travel time, make sure that you give yourself six hours."

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.