Northwest Mountains

Avalanche conditions slowly improve as time increases from the major loading event on Sunday.  You can trigger an avalanche on recently drifted slopes and in sheltered areas.  Use caution around slopes with signs of fresh drifting and avoid slopes that seem shallower than average for the area.  Impacting weak layers and releasing an avalanche is more likely where the snowpack is shallower due to wind erosion, previous avalanche activity, and rocky terrain.  If you choose to play in avalanche terrain you can hedge your bet by selecting smaller slopes with clean runouts free from terrain traps.

Light snowfall and some wind transport continue on Wednesday.  The current weather is not expected to have a significant impact on today's conditions.  Cloudiness has hampered natural avalanche documentation in both forecast zones since the major loading on Sunday and Sunday night.  A brief period of clearing yesterday allowed observers to see portions of the Northwest Mountains (although not the highest terrain along the spine of the Ruby Range) and only a single natural avalanche was observed on the Shield in Redwell Basin.  Some uncertainty lingers about recent natural activity on the most drifted terrain along the Ruby Range.  Similarly, poor views in the Southeast Mountains have left few documented natural avalanches, but the activity recorded Monday on Whetstone reinforces the concern and poorer avalanche conditions in the shallower Southeast Mountains.  Regionally, several very large avalanches have been recorded in the Aspen area (1,2,3).  The snowpack in these areas around Aspen is similar to the Southeast Mountains forecast zone.

The Northwest Mountains offer a lower risk of triggering a dangerous avalanche.  Weak layers are covered by thicker and stiffer slabs which helps to insulate the weight of a backcountry traveler.  Even though there is a reduced risk, the threat of human-triggered avalanches lingers.  You can reduce your risk by avoiding slopes with signs of recent drifting; drifted slopes will be commonly found at upper elevations on the east half of the compass.  Cornice fall is one mechanism for a very large avalanche to release so give these recently grown hangers a wide berth. Steer clear of slopes that appear to be shallower than expected due to previous avalanche activity this winter, eroded by winds, or have rocky and irregular terrain shape.  All of the scenarios that you want to avoid involve thinner slabs where you have an increased likelihood of impacting weak layers.  You can also reduce risk by selecting terrain with lower consequences (small slopes free from terrain traps).

In the Southeast Mountains, the overall shallower snowpack increases the chance you find a trigger point and in some portions of the zone the snowpack is shallow enough that slabs remain at optimal depths for human-triggered avalanches.  Examples of terrain with the shallowest snowpack can be found immediately adjacent to the town of Crested Butte, Whetstone, lower Brush Creek, and lower Cement Creek.  Prior to the recent storm, a forecaster on Cement Mountain reported very poor structure on the same day another party triggered an avalanche one basin away.  The same snowpack now has a foot or more of recent snow further stressing buried weak layers.  Take a cautious and conservative approach to your terrain selection in the Southeast Mountains if you travel over terrain highlighted by the Persistent Slab rose.  You can find lower-risk options below treeline on sunny terrain where the recent storm snow sits above thicker and supportive crusts.