Avalanches and mitigation work caused delays Monday on Lizard Head and Wolf Creek passes as well as on passes in the U.S. 550 mountain corridor.

Snowslides happened Sunday in the area, but no injuries occurred, CDOT said. Lizard Head and Wolf Creek pass reopened at noon Monday, CDOT said, and Coal Bank and Molas passes reopened by 5:30 p.m.

On Monday, the threat of avalanches was rated “moderate” in the southern and northern San Juan Mountains, and “high” in Colorado’s central and northern Rockies.

Five to 10 inches of dense snow fell in the past 24 hours in the San Juans, the Colorado Avalanche Information Center said.

“Winds are drifting snow into slabs up to four feet thick especially on easterly-facing slopes,” CAIC said. “Storm snow is falling on a variety of old snow surfaces and may not bond well to firm underlying crust or wind-stiffened surfaces. ”

Wolf Creek Ski Area reported Sunday evening that it received 18 inches of snow in the preceding 24 hours and 22 inches in the preceding 48 hours.

Colorado Highway 145 at Lizard Head Pass was closed Monday morning and reopened about noon, CDOT said.U.S. 160 at Wolf Creek Pass was closed from 6 a.m. to noon, CDOT said.Eastbound traffic was stopped near the chain-up station at Treasure Falls, mile point 157. Skiers were advised to arrive at this point before 6 a.m. in order to reach the ski area.

Westbound traffic was stopped at the pass summit, mile point 167. Skiers traveling westbound could reach the ski area throughout the day, since the closure point is west of the resort.

By 5:30 p.m., Coal Bank and Molas passes had reopened. Avalanche work continued Monday evening on U.S. 550 at Red Mountain Pass, and there was no estimated time that it would reopen. CDOT said snow slabs, 10 to 30 feet deep in some areas, had fallen into the highway, and debris on the highway included limbs and trees.