Avalanche Forecast

Low - Forecast snowfall amounts are uncertain

Snow forecasts identify the largest snowfall amounts occurring in the St Mary's drainage area of the Purcells forecast region.MONDAY NIGHT: Cloudy with flurries / Accumulation: up to 10 cm / Alpine temperature: Low -1C / Light southwest ridge wind / Freezing level 1500mTUESDAY: Cloudy with flurries / Accumulation: up to 15 cm / Alpine temperature: High +1C / Light to moderate southwest ridge wind / Freezing level 1500mWEDNESDAY: Cloudy with sunny breaks and flurries / Accumulation: up to 5 cm / Alpine temperature: high 0C / Moderate decreasing to light southwest ridge wind / Freezing level 1600mTHURSDAY: Cloudy with sunny periods / Accumulation: trace / Alpine temperature: High -1C / Light ridge winds

On Saturday, a large human triggered avalanche was reported in the South Columbia forecast region. The size 3 avalanche occurred on a steep, north aspect in the alpine and failed to ground, likely on the October crust. This avalanche is notable for the Purcells where we have a similar, but shallower snowpack than in the South Columbia, resulting in a higher possibility of impacting a weak layer near the ground. Find the MIN report here.Small windslabs have been triggered by skiers and explosives in cross-loaded and lee terrain features at treeline and alpine elevations. Earlier in the month, a natural avalanche cycle took place over the late October crust/facet combination. Be aware of the continued possibility for smaller avalanches to 'step down' or even initiate at this deeper layer.

Snowfall through Monday afternoon has deposited up to 10 cm around the region. This added to recent snow, has buried a surface hoar/sun crust layer down about 10-30 cm. Reports in the region show this variable layer sitting above a layer of recently reactive wind slab. This wind slab layer overlies yet another widespread layer of surface hoar from mid-November, now found about 30-50 cm deep. A final, prominent feature of the snowpack is a combination of a melt-freeze crust and underlying sugary, faceted snow found around the base of the snowpack. Avalanches have been triggered where there is a slab above this crust.