Avalanche Forecast

Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

A ridge of high pressure brings warming and sunny skies through the weekend. Valley bottoms may see some valley cloud trapping cooler air down low.

Saturday: Freezing levels rise through the day to 2000-2500 m with generally clear skies. Possible inversion especially in tighter valleys may hold valley cloud and cooler temperatures down low. Ridgetop winds moderate from the northwest. Expect some cooling overnight.

Sunday: Sunshine and freezing levels hovering around 2000-2500 m. Strong northwest wind. 

Monday: Freezing levels forecast to drop to 1000 m.

On Friday morning the field team reported four new wind slabs size 2.5 to size 3 that looked to fail on the (re-loaded) early December interface in the Crowsnest North. One of these appeared to be triggered by a cornice fall.

Sunshine, warm weather, and a complex snowpack are concerning this weekend. Smaller surfaces avalanches and cornice fall could trigger deep persistent slabs. This layer has been dormant but to no surprise could wake up. 

Strong winds have redistributed the recent storm snow from earlier this week onto leeward slopes forming stiff and reactive wind slabs. The wind slabs prove to be more reactive where they sit above older hard snow surfaces or a crust. 

The upper snowpack is variable throughout the region with a melt-freeze crust found 10-20 cm down (aspect and elevation dependant) in some locations to barely existing in other locations, especially above 2000 m. One common theme throughout the region is that the mid-pack is well settled above the deeper December crust/facet interface which is currently the primary concern in the snowpack.

The early December crust is now generally down 80-150 cm. This layer is found widespread through the region but with varying test results. Recent snowpack tests have shown more reactivity in shallower snowpack areas as well as reactivity to step down avalanches. This indicates that there is potential to trigger this weak layer from a thin spot which may propagate to a thicker slab within the snowpack. In turn, triggering a very large avalanche. 

Most concerning is the warm weather this weekend and its effect on the complex snowpack. Warming, solar radiation, and cornice fall could all play a role in triggering deep persistent slabs. This layer has been dormant but to no surprise could wake up. 

• Cornices become weak with daytime heating.
• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
• Back off slopes as the surface becomes moist or wet with rising temperatures.