Weekend Avalanche Outlook

Heightened avalanche conditions in Chugach State Park this weekend: evaluate snow and terrain carefully; identify features of concern.

Avalanche concerns:

Persistent slabs up to D2.5 in size are possible above 3000′ on terrain steeper than 35 degrees.  Steep, leeward (primarily west to north), broad, and open slopes in the upper elevations are expected to be the most problematic.  Widespread buried surface hoar was found in the South Fork Eagle River area with very concerning snowpit test results on 1/24/16 and 1/29/16.  This persistent weak layer may be patchier elsewhere in Chugach State Park but likely exists in upper elevation areas throughout the park, especially on the more sheltered and typically lee west to north aspects.  This layer is likely 1-2+’ deep where most problematic.  It is relatively easy to identify in snowpits, and an Extended Column Test (ECT) is one good way to gauge energy and propagation propensity.

Winds slabs up to D2 in size are possible above 2500′ on terrain steeper than 35 degrees.  Steep, leeward (primarily west to north) terrain especially where winds are channeled (i.e. passes, cols, saddles) are expected to be the most problematic.  Clues to identify include snow surface texure (etched, or light sastrugi), denser/firmer snow that has been wind-packed, and cracks radiating from your feet.  Pole probing and quick handpits will be an effective way to get a handle on the wind slab problem.

Loose dry avalanches, or “sluffs”, are likely on terrain steeper than 35-40 degrees on any aspect where the few+ inches of fresh, dry snow sits on a base.  These are expected to be low volume and of moderate speed.  Exercise sluff management techniques and be mindful of exposure and terrain traps.

The danger is expected to decrease through the weekend, but will increase if winds happen to pick up as there is plentiful loose snow available for transport.