Colorado: Incoming storm will up the avalanche danger

The avalanche danger is rated as considerable on wind-loaded slopes at higher elevations Sunday, but forecasters with the CAIC expect to raise the danger later today or tomorrow as a windy storm barrels in from the northwest. Click on the image to get the latest info from the CAIC.

Several recent slides reported from East Vail, Vail Pass area

By Summit Voice

SUMMIT COUNTY — Forecasters are keeping a close eye on an approaching weather system that could drop one to two feet of snow across parts of the north-central mountains and up the avalanche danger early next week. Gusty winds out of the northwest could add significant wind slab to slopes above treeline.

See the special advisory statement from the CAIC here.

As of Sunday morning the avalanche danger is rated as considerable near and above treeline on north through east through southeast-facing slopes, with the potential for triggering wind slab in many areas, especially on cross-loaded slopes and gullies. Of special concern are persistent weak layers in the upper part of the snowpack, including surface hoar layers that formed during recent cold spells. On other slopes the danger is rated as moderate.

You can follow the CAIC’s forecast for your part of Colorado by clicking here.

Backcountry observers have reported that those layers are quite reactive to snow stability tests, so digging a snow pit and doing compression tests is worthwhile before tackling a steeper slope.  You can report your own backcountry observations here.

Here’s an excerpt from the Jan. 14 CAIC bulletin describing the situation:

“There are several buried persistent weak layers to be attentive too. More recently, one to two surface hoar layers were buried intact and are producing consistent results in test scores. Buried surface hoar is not as common as faceting in the zone but can remain weak and reactive for weeks if not months to come. Around here, surface hoar of this size is typically destroyed by the wind and sun before it is buried. So, this weak layer is somewhat new to many backcountry travelers. Another lingering weak layer is buried deeper. This layer rests between two stiff slabs and is only and inch or two thick. Small buried surface facets are the culprit here. This layer may be able to handle a lot of stress but has the ability to propagate a fracture large distances.”

The CAIC also reported a couple of recent avalanches, one from the East Vail backcountry on on east-facing slope near treeline that may have been triggered by a falling cornice before running nearly 800 feet.  A second slide in the Vail Pass area was triggered by a skier and ran about 300 feet.

Get more details here …


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