Avalanche Forecast

Fair - Intensity of incoming weather systems is uncertain

Wednesday night: 5-15cm of new snow / Strong southwest winds / Freezing level at about 900mThursday: 10-15cm of snow / Moderate southwest winds / Freezing level at about 1500mFriday: Light snowfall / Moderate to strong southwest winds / Freezing level at about 1500mSaturday: 10-15cm of snow / Moderate to strong southwest winds / Freezing level 1600-2000m

Although observations were limited on Tuesday, several storm slabs to size 1.5 were observed on all aspects in alpine terrain. In recent days, 3 persistent slab avalanches in the 2-2.5 range were triggered naturally or remotely close to Invermere. Over the past week in the Dogtooth Range skiers initiated a cornice fall which triggered a size 2.5 slab avalanche on the slope below. In the same area a size 2 slab was rider triggered from a ridge crest. The February 10th interface was the culprit in these events.I expect avalanches to increase in size and frequency with forecast weather.

Although snowfall amounts have been highly variable throughout the region, in some deeper snowpack areas over 80cm of storm snow overlies weak surface hoar in sheltered areas, a sun crust on solar aspects and wind slabs in exposed terrain. On lee slopes these accumulations have been pushed into much deeper deposits by generally moderate southwest winds. Ongoing snowfall, wind and warming will add to the reactivity and destructive potential of this developing storm slab.There is ongoing concern for a mix of weak surfaces which were buried on February 10th. This persistent interface lies between 60 and 150cm below the surface, and includes surface hoar, well developed facets and a mix of hard surfaces which remain widespread at all aspects and elevations. In some areas destructive avalanches are still a real concern with recent reports of natural triggering, whumpfing and sudden/easy snowpack test results. The mid and lower snowpack are generally strong and well consolidated. Weak basal facets exist in many areas, but triggering has now become unlikely.