The Lionhead and Island Park areas received less snow than the rest of our forecast area this week and avalanches are unlikely. Keep an eye out for isolated areas with drifts sitting on weak, sugary snow.
Look out for wind drifts more than a couple inches deep that are sitting on weak snow from the January dry spell, without a thick crust between them.
Avalanches are possible to trigger where snow from early in the week created thick slabs on top of weak layers that formed during dry weather in January. Steep slopes with 8-12” of snow or more sitting on sugary, weak snow is enough for an unstable setup, and is where a person could trigger an avalanche.
Be cautious of steep slopes where recent snow was drifted into thicker slabs. In areas where more snow fell, like near Cooke City and the southern Madison Range, even non-wind-loaded slopes can have enough snow to cause a persistent slab avalanche. This problem can be tricky to assess right now because the weak layer varies in existence and strength (video). It has been destroyed by tracks, wind or sun on some slopes, and on some slopes it has a thick crust above it making avalanches less likely.
You might see warning signs like collapsing and cracking, or unstable snowpack test results, but you might not. Yesterday in the Taylor Fork area a snowmobiler triggered an avalanche about a foot deep and a hundred feet wide (observation and photo), and another rider saw a recent natural avalanche (observation and photo). Ian was at Bacon Rind in the Southern Madison Range yesterday, and he had large collapses and easily found an unstable snowpack structure (observation, video), while the day before he did not see any signs of instability just a short distance away in Tepee Basin (observation). Near Cooke City yesterday, a skier triggered a small avalanche, notably after the first skier had ski-cut the slope without triggering the slide (observation).
The likelihood of triggering avalanches is decreasing, but the possibility remains. If you choose to travel on steep slopes choose smaller slopes where avalanches won’t break as large. Although potential avalanches will be relatively shallow, they can break wide on big slopes, like this slide observed near Cooke City (observation). Find slopes without hazards like trees or cliffs that increase the chances of injury, or gullies where small slides can pile up deep. The avalanche danger is MODERATE in the Bridger, Madison and Gallatin Ranges and Cooke City.
In the Lionhead and Island Park areas, there was less recent snowfall, avalanches are unlikely, and the avalanche danger is LOW. Keep an eye out for isolated areas with drifts sitting on weak, sugary snow. A skier triggered a small slide yesterday near Hebben Lake which was only a small drift, but it entrained weak, sugary snow and ran a long distance down a steep slope (observation).
