Pay attention to how the new snow reacts under your skis or track and how it changes throughout the day. Several types of dry snow avalanches are possible, especially wind slabs near ridgelines. As the day warms up with some sunshine poking through the clouds, watch for the new snow becoming damp. Avoid pillows of wind drifted snow, and if you see any red flags in the new snow choose lower angle terrain.
With so much new snow and various avalnache problems possible, be conservative and cautious in your terrain selection.
Wind slabs will be larger and easier to trigger at higher elevations but look for them at mid elevations as well. Watch for increasing winds from the south later today.
The new snow will only have to become damp to make wet loose slides. They will be most likely on sunny slopes, but thin clouds may scatter the solar radiatio and warm slopes that are typically shaded.
With so much snow, watch for any indication that it is cohesive and could make a soft storm slab avalanche. It may easily sluff as a dry loose avalanche in steep terrain.
Welcome to April with a typical pattern of spring weather and avalanche concerns with many types of avalanches possible within the span of a day. Pay attention to changing conditions (video). The slightest bit of wind, temperature changes, or sun vs clouds can completely change how the new snow reacts.
Yesterday’s new snow became damp and was able to sluff easily on an ice crust underneath it as Ian found near Bridger Bowl and as the Big Sky Ski Patrol observed on Lone Mountain. The snowpack underneath the new snow is generally refrozen and stable.
Cooke City has gotten 15” of snow since Monday, and several different types of avalanches within that snow are possible making the avalanche danger CONSIDERABLE at upper elevations. Near ridgelines, there should be pillows of wind drifted snow from mostly southwest winds yesterday that can produce wind slab avalanches. On slopes without any drifts, pay attention to how the new snow responds as you move around:
In all other areas, less snow has fallen and the avalanche danger is MODERATE. There may be drifts that can make wind slab avalanches. Depending on how much warming happens today, the snow may again slide easily as a wet (or slightly damp) loose avalanche. These slides often start at your feet, but can also start on their own in steep terrain near rocks that get especially warm.
NOTE about spring conditions - Snow and avalanche conditions change as fast as the weather. We have to be attentive and willing to change our plans just as quickly. Sometimes new snow can make dry snow avalanches in the morning, stabilize midday, and then make wet snow avalanches in the afternoon.
NOTE about Bridger Bowl - The ski area is now closed and open for uphill travel with backcountry conditions. There is no ski patrol performing avalanche mitigation or ready to help if you get hurt. Our terrain selection has to be different than when the ski area is operating. Even a tiny avalanche can sweep you off your feet and over cliffs and rocks causing major trauma.
