A winter weather advisory remains in effect until 6 a.m. Monday, with 4 to 8 inches of snow forecast for the mountains of Western Colorado.
The National Weather Service said Saturday that up to 14 inches of snow could fall in isolated mountain areas.
Wind gusts are expected to reach 35 mph, and mountain drivers should count on low visibility, drifting snow and slick roads, the weather service said.
As of 1 p.m. Sunday, a chain and traction law was in effect for Coal Bank and Molas passes on U.S. Highway 550, between Durango and Silverton.
As a result, chains or alternative traction devices are required for all commercial vehicles, including buses and vans that have a capacity for 16 or more people. Passenger vehicles must have snow or mud/snow tires, use chains/alternative tractions devices or have a four-wheel drive/all-wheel drive vehicle.
As of 5 p.m., a chain law was in effect for Wolf Creek Pass between Pagosa Springs and South Fork, as well as Lizard Head Pass between Rico and Telluride. Chains or alternative-traction devices are required for all commercial vehicles, including buses.
Weather advisories and warnings are issued when a hazardous weather or hydrologic event is occurring, imminent or likely, the weather service said. A weather watch is used when the risk of a hazardous weather or hydrologic event has increased significantly, but its occurrence, location or timing is still uncertain.
As of 5 p.m., Purgatory Resort reported 3 inches of new snow. Wolf Creek Ski area reported 4 new inches of snow.
The Four Corners area increasingly needs more precipitation. Drought conditions already exist in Montezuma County, and mountain snowpack levels in the region are at 49 percent of average and 37 percent compared with last year’s level, according to the Natural Resources Conservation Service.
In Montezuma County, Sunday’s overnight low was expected to be about 16 degrees. Sunny skies are expected on Monday, with a high near 41 degrees and an overnight low around 20.
Temperatures are expected to rise to nearly 60 degrees as the week progresses, with possible showers on Thursday and Friday.
Jonathan Romeo of The Durango Herald contributed to this article.