Avalanche Forecast

Thursday night: Cloudy with flurries bringing a trace to 5 cm of new snow.. Light northwest winds shifting northeast and increasing.

Friday: Cloudy with isolated flurries and up to 5-15 cm of low density new snow, mainly in the south, continuing overnight. Moderate to strong northeast winds increasing over the day. Alpine temperatures dropping to around -17.

Saturday: A mix of sun and cloud. New snow totals of 10-20 cm. Light to moderate northeast winds. Alpine high temperatures around -20.

Sunday: Sunny. Light northeast winds. Alpine high temperatures around -12.

Up to 15 cm of new snow and strong winds were observed forming reactive wind slabs throughout the region on Tuesday. More recent wind slab formations may remain reactive to human triggering with touchier new slabs expected to form under a shift to strong northeast winds.

Pemberton SAR responded to a cornice collapse involvement in the Duffey Lake area on Monday when a large chunk of cornice released and collided with a rider in steep terrain on a lower elevation (1700m) feature. The impact of the cornice failed to trigger a slab but it did entrain loose snow that contributed to the full burial of the subject. 

On Sunday there was a skier triggered size 2 persistent slab avalanche in the north of the region that is suspected to have run on weak facets that were buried in late November. It was on a northwest aspect at 2200 m and may have been a slope that had slid previously and was reloaded.

On Friday, explosives triggered cornices and 20 cm slabs within the recent storm snow, producing small (size 1 to 1.5) up to large (size 2) avalanches. The avalanches were on west to north aspects and at alpine elevations. A persistent slab avalanche was triggered by a rider in the northern part of the region, likely releasing on the February 22 surface hoar layer described in our Snowpack Summary. The avalanche was large (size 2) and occurred on a north aspect in the alpine.

5 to 15 cm of new snow accumulated in the region during Tuesday's storm, accompanied by moderate to strong south and west winds. Wind slabs up to 30 cm deep have been observed on leeward slopes. The new snow also buried surface hoar in more sheltered areas as well as sun crusts on south-facing slopes.

Another weak layer of surface hoar crystals and/or faceted grains may currently be found around 50 to 80 cm deep. The distribution of this layer is spotty, likely existing as a problem only in isolated steep, sheltered, north-facing slopes at mid elevations. Professionals throughout the region have begun to consider it dormant.

In the northern part of the region (i.e., Duffey/Hurley/Gold Bridge), a deep instability may linger at the base of the snowpack. It has not produced an avalanche since February 17th. Human-triggering is unlikely, though if one were to trigger the layer, it would likely be in a thin, shallow, rocky spot. A large load, such as from a cornice fall, or sustained warm temperatures have the potential to trigger this layer.

• Avoid freshly wind loaded terrain features.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.
• Watch for avalanche hazard to increase throughout the day.