Avalanche Forecast

Fair - Forecast snowfall amounts are uncertain

Tuesday: Freezing levels will go up on Tuesday with light to very light precipitation expected, light to moderate sw winds at ridge tops.Wednesday: Forecast models differ in precipitation amounts and intensity, but generally agree that Wednesday will have the most snowfall.  10 to 20 cm  forecast for the Purcells.Thursday :  Arctic air moves into the southern part of the province bringing freezing levels to valley bottom.

Wind slabs overlying surface hoar and facets have become touchy. The possibility of triggering large and destructive avalanches is high. Recent reports speak of shooting cracks and widespread propagation in the storm and wind slabs. The potential exists for large destructive avalanches with increased loading and wind transport.

Small amounts of recent storm snow are beginning to add up on top of the sugary facets from early December. Snowpack depths at tree line currently vary from 100- 130 cm and reports speak of severe scouring on the windward side of ridges, moving snow onto lee sides and creating dense wind slabs.. A persistent weakness of buried surface hoar and facets is down approximately 20-40cm . This layer has been producing variable results with snowpack tests. Recent reports indicate that the new storm/wind slab is becoming reactive with warming temperatures and additional loads. At the base of the snowpack are weak facets and depth hoar combined with a crust from early October.. This deep persistent weakness may be stubborn to trigger, especially in deeper snowpack areas, but the sensitivity to triggers likely increases in shallower locations, especially on steep, convex slopes. At lower elevations the snow depth is below the threshold for avalanches.  With increasing load the weak layers may become more reactive.