Avalanche Forecast

Moderate - Uncertainty is due to the limited number of field observations. Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Light to moderate snow and strong wind will arrive with the forecast strong Pacific frontal system.

Wednesday: Snow 5-10 cm accumulating through the day. Alpine temperatures near -3 and freezing levels valley bottom. Ridgetop wind strong from the South.

Thursday: Snow 10-20 cm. Alpine temperatures -3 and freezing levels 900 m. Ridgetop wind switching to the southeast.

Friday: Cloudy with isolated flurries. Alpine temperatures near -5 and freezing levels 600 m. Ridgetop wind moderate from the southeast.

A new MIN report submitted on Tuesday showed a deep release from a leeward high alpine feature. The deep persistent slab problem may be isolated, however; a high consequence exists if you find yourself involved in an avalanche of this size.

On Sunday a human triggered slab avalanche size 2 was reported which started as a wind slab or storm slab and then stepped down to the early December persistent weak interface. The person was caught and partially buried. Reports from Saturday continued to highlight the instability of slabs that have formed above the early December rain crust. Check out this notable step-down release from the Hankin-Evelyn area.

Please consider sharing your observations to the Mountain Information Network. Thank you to those that have already submitted this winter!

Incremental loading of new snow has given us 30-50 cm of recent snow. This was redistributed by recent southwest winds in exposed areas but likely remains lower density in more sheltered areas.

This recent snow sits on an early-December melt-freeze crust with weak and sugary faceted grains around it. This layer has featured in several avalanche reports that can be found on the MIN. This interface is currently reactive to human triggering and producing size 2 avalanches.

 

A crust that was buried in early November is near the base of the snowpack. This crust has weak facets associated with it. These facets have produced large avalanches in both the south and north of the region. Friday's reports of whumpfs suggest this layer should still play a role in guiding your terrain selection.

Snowpack depths vary substantially with aspect, elevation, and wind exposure. 

• In times of uncertainty conservative terrain choices are our best defense.
• Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
• In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.