Up to a foot of snow is possible near Red Mountain Pass as a fast-moving Pacific storm started dropping snow on the San Juan Mountains and much of central Colorado on Monday afternoon, according to the National Weather Service.
A winter weather advisory is in effect until 6 p.m. Tuesday for affected areas, including Silverton, Ouray, Telluride, Lake City, Crested Butte, Aspen and Vail.
The light snow that began to fall Monday afternoon is expected to increase in intensity, the weather service said.
Durango had a 30 percent chance of snow Monday night and Tuesday, the weather service said.
Much of the area under the winter weather advisory could get 4 to 8 inches of snow, which are expected to come with 10 to 20 mph winds and gusts up to 30 mph.
Shortly before 2 p.m., the National Weather Service said snow had started near Crested Butte and Monarch Pass.
A strip along the Sangre de Cristo Mountains is under a winter storm warning and whiteout conditions are possible.
The wintry conditions are expected to make travel difficult in some areas, especially mountain passes.
The chain law went into effect just after 2:30 p.m. Monday on U.S. Highway 550 at Red Mountain Pass, meaning chains are required on commercial vehicles and chains or snow tires are required on other vehicles.
It also is in effect on U.S. Highway 160 on Wolf Creek Pass and U.S. Highway 50 at Monarch Pass, where multiple crashes on Monday evening closed the highway, according to the Colorado Department of Transportation.