Backcountry skiers, riders, snowshoers and snowmobilers beware.

An atmospheric river bringing heavy snowfall to Colorado this week could be setting up a very dangerous avalanche cycle over the coming days. Forecasts of 1-3-plus feet of snow by Thanksgiving are a real probability. 

These factors have led to the Colorado Avalanche Information Center (CAIC) issuing an avalanche watch from 5 p.m., Tuesday to 5 p.m., Wednesday for much of the state’s high-country slopes in the West Elk Mountains.

“We’re particularly worried because we’ll see the most dangerous avalanche conditions we’ve seen so far this season when more people than usual will be getting out to recreate because of the holiday,” CAIC Director Ethan Greene said.

The CAIC said the rapid and heavy snowfall combined with an already weak snowpack will lead to dramatically different and significantly more dangerous avalanche conditions than seen so far this season.

Avalanche danger is expected to reach HIGH (Level 4 of 5) in favored areas by Tuesday night, with large, dangerous avalanches possible.

“There will be an increased likelihood of natural and human-triggered avalanches that are large enough to seriously injure or kill a person this week,” Greene said.

The CAIC issues avalanche danger ratings based on the North American Public Avalanche Danger Scale from LOW danger (Level 1) to EXTREME danger (Level 5).

According to the CAIC, during certain avalanche conditions, the agency also issues Avalanche Watches and Warnings when the avalanche hazard will be or is HIGH (Level 4) or EXTREME (Level 5).

Special Avalanche Advisories are issued to alert the public of an increased safety risk due to potentially dangerous conditions for many people, such as a big storm occurring during a holiday weekend.

The CAIC has recorded two avalanches in Colorado in winter 2024-25 so far, both in the month of November, with one near Berthoud Pass in Grand County and the other near Red Mountain Pass in San Juan County.

“The avalanche danger is going to be higher and avalanche conditions are going to be trickier this coming week than what we’ve seen so far this season,” Greene said. “There are still lots of great, safe places to go. We want people to check the avalanche forecast and make a plan that keeps them out of avalanche terrain or off of the dangerous slopes.”

Forecast Timeline:

• Tuesday: Avalanche danger will increase to HIGH (4 of 5) in the West Elk Mountains and CONSIDERABLE (3 of 5) in many other areas.

• Wednesday: Snowfall totals may reach three feet in areas like the Park Range, Flat Tops, and Elk Mountains, with two feet or more across most mountains Avalanche danger will likely reach HIGH (4 of 5) in much of the Northern and Central Mountains, and in the western San Juan mountains.

• Thanksgiving: Avalanche conditions are expected to remain very dangerous (CONSIDERABLE (3 of 5)

• Friday–Sunday: While the storm ends late Wednesday or early Thursday, dangerous avalanche conditions will continue as the snowpack adjusts to this rapid load. With clear skies, fresh snow, and the holiday weekend, backcountry activity will likely increase. Special Avalanche Advisories are anticipated.

This timeline is subject to change. For the latest avalanche conditions, always visit CAIC’s website at Colorado.gov/avalanche.

The CAIC strongly advises all backcountry travelers to check the avalanche forecast regularly and adjust their plans accordingly.

The CAIC also advises to always carry proper avalanche safety gear, including a transceiver, probe and shovel and know how to use them, and avoid avalanche-prone terrain during periods of heightened danger.