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Colorado: Backcountry avalanche watch issued

Snow Thursday night could set off another natural avalanche cycle

Parts of the Colorado mountains are under an avalanche watch. Click for more info.

By Summit Voice

SUMMIT COUNTY — A round of forecast snow — perhaps 4 to 10 inches Thursday night — could unleash another cycle of dangerous, naturally running backcountry avalanches, Colorado snow safety experts said, issuing an avalanche watch that covers the Front Range and mountains to the west from Fairplay up to Steamboat Springs.

Four people have died in avalanches this season, including two at ski areas. Get the latest backcountry update at the Colorado Avalanche Information Center website.

An avalanche watch means that, if the weather forecast is accurate, the avalanche danger will rise to high in the watch area, with both natural and triggered slides likely. The watch is in effect through 11 a.m. Friday. A high danger rating means very dangerous backcountry avalanche conditions, and travel in avalanche terrain is not recommended. Specifically, the warning covers the Park Elkhead, Flattop, Front, Gore and Tenmile ranges.

The forecast calls for a 12 to 18 hour period with moderate to heavy snow and strong winds building fresh layers of snow atop a rotten base of faceted sugar-snow crystals that can’t support additional weight.

Freshly fallen dendritic snow crystals. When these flakes fall and sit on the ground during spells of dry, cold weather, they metamorph into so-called faceted grains (see next photo) that don't stick together and can't support the weight of subsequent snow layers. PHOTO BY BOB BERWYN.

These area faceted grains of "sugar snow" at the base of the snowpack in most of Colorado's mountains. They don't stick together and collapse easily under the weight of fresh snow, contributing to the significant risk of backcountr avalanches.

Some avalanche paths that slid after the last storm cycle have already been reloaded by wind-transported snow and the weight any fresh snowfall is likely to cause more natural releases.

Scores of natural and triggered avalanches have been reported the past few days from around the state, with some slides taking the entire snowpack to the ground. See the full list of recent avalanche observations at this CAIC web page.

The snowpack is tender and touchy, as shown by this video from the CAIC YouTube channel:

This video is posted at the CAIC’s latest backcountry avalanche conditions report web page.

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