Backcountry: Spring avalanche danger spiking

Wet snow slides likely near and below treeline

A wet snow slide in the Tenmile Range near Breckenridge.

SUMMIT COUNTY — A couple of large, skier triggered slides in the Tenmile Range show that spring-like weather will lead to a spike in the backcountry avalanche danger.

With overnight lows barely dipping below freezing in many areas, the snowpack on steeper, sunny slopes will become more unstable, with a good chance of wet snow slides, especially below rock bands and cliffs as the day progresses.

Overall, conditions are “a go” for backcountry activities, but timing and route selection are key to safe travel, the Colorado Avalanche Information Center said in its Saturday morning bulletin, rating the avalanche hazard as considerable on all slopes near and below treeline because of the potential for wet snow slides. At higher elevations, the danger is rated as moderate. A “considerable” rating means both natural and triggered avalanches are likely.

For now, the forecasters say it could be smart to avoid travel in below-treeline areas for a few days, where wet snow slides could be large and destructive and carry backcountry travelers over cliffs and into trees.

During this transition season, backcountry avalanche hazards can vary dramatically from day to day and from slope to slope. Overnight temperatures well below freezing help to stabilize the snowpack, while warm and sunny days quickly lead to free water percolating down through the snow where it can lubricate a slab when it hits a solid layer like a crust.

Here’s an excerpt from the March 19 avalanche bulletin:

“If you find yourself collapsing in cohesion-less wet snow, re-evaluate your location and consider turning around. Wet snow avalanches have a strong grip and are very destructive.

Pay close attention to natural signs of instability and travel from safe zone to safe zone. Keep a close eye on how wet the snow surface becomes. Triggering an avalanche today in the alpine is possible. If you do trigger an avalanche, they will likely be small in size, though large avalanches are not out of the question. Dry slab avalanches could turn into destructive wet avalanches if they travel to lower elevation runouts. Tread lightly today and enjoy the new snow.”

Check in with the CAIC for daily updates on the web, or call the Summit hotline at (970) 668-0600.


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