According to the Oregon Department of Transportation, Highway 66 between Ashland and Klamath Falls is closed. Other highways near Crater Lake are also closed, including Highways 230 and 138.
Along I-5, chains are required heading over the Siskiyou Summit south of Ashland. Cars heading northbound will be checked for chains at Yreka, according to Caltrans. ODOT is reporting up to a two-hour delay on I-5, because of chain restrictions.
Chains are also required on cars traveling on I-5 between Redding and Mount Shasta, and on other mountain highways east and west of Redding.
According to the National Weather Service, a winter storm warning is in effect through 4pm on Wednesday across much of the region. Snowfall is expected in areas above 2,000 feet, and could be as high as a foot in some places. Elevations above 4,000 feet could also see up to two feet of snow accumulation.
Travel is highly discouraged, especially on mountain roads, the NWS says. Blowing snow could create whiteout conditions and make travel very difficult. Wind gusts of up to 30 mph are expected along Highway 97 and I-5.
The weather service says if you must drive, carry emergency supplies with you, including tire chains, blankets, food and water.
Conditions are expected to improve as the day continues.
The latest road conditions can be found in Oregon at tripcheck.com, and in California on the Caltrans website.