SACRAMENTO, Calif. (NewsNation Now) — A Pacific storm brought much-needed rain and snow to California on Wednesday at the tail-end of a largely dry winter.

Winter storm warnings were in effect in the southern Cascades, down the length of the Sierra Nevada and the mountains of Southern California. Caltrans urged drivers to check for chain controls.

Conditions included showers, downpours, thunderstorms, hail and low-elevation snow.

By the afternoon, the California Highway Patrol said a jackknifed big rig and multiple spinouts were causing traffic backups on Interstate 80 in the Sierra.

One person was hospitalized Wednesday when a car crashed into the Feather River in Butte County.

Around 7:45 a.m., Cal Fire said firefighters and a swift water rescue team responded to the river along Highway 70, in the area of Pacific Gas and Electric’s Cresta Powerhouse.

A sedan was found partially submerged in the water next to the slick roadway. Cal Fire says driving conditions in the area were “very treacherous” as a winter storm passed through.

One person was out of the car and appeared to have minor injuries, according to Cal Fire.

In the Eastern Sierra, the Mammoth Mountain ski resort reported 13 inches to 15 inches of new snow, with more expected.

The Sierra snowpack is an important part of California‘s water supply, but at the start of March its water content was about half the average normally recorded on April 1, when it is typically at its most robust.