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Avalanche Forecast

Jan 14th, 2021–Jan 15th, 2021
Alpine
3: Considerable
Treeline
3: Considerable
Below Treeline
2: Moderate
Alpine
3: Considerable
Treeline
3: Considerable
Below Treeline
2: Moderate
Alpine
3: Considerable
Treeline
2: Moderate
Below Treeline
2: Moderate

Regions: Lizard-Flathead.

Human triggered avalanches remain likely as strong winds are expected to form fresh slabs throughout the day. Look for low-angle, sheltered slopes for the best, and safest riding.

Confidence

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Weather Forecast

THURSDAY NIGHT - Mainly clear / light to moderate west wind / alpine low temperature near -5 

FRIDAY - Sunny with cloudy periods / strong west wind / alpine high temperature near -4 

SATURDAY - A mix of sun and cloud / light to moderate west wind / alpine high temperature near -7 

SUNDAY - Mainly cloudy with sunny periods and isolated flurries / strong west wind / alpine high temperature near -5

Avalanche Summary

With strong west winds in the forecast and a lot of fresh snow available to blow around, storm and wind slabs are expected to be easy to trigger on Friday, especially in wind loaded areas.

On Thursday there were numerous reports of explosives triggered avalanches up to size 2.5, including one size 2.5 persistent slab avalanche.

There was a widespread natural avalanche cycle with avalanches up to size 3 reported on Tuesday night and during the day on Wednesday. There were also reports of numerous explosives triggered avalanches up to size 2.5, one of which was a persistent slab avalanche.

Over the past week, there have been several natural and persistent slab avalanches between size 2.5-3 reported in the region. These avalanches are continued reminders of the "low probability; high consequence" scenario that persistent slab problems often create. 

Snowpack Summary

The region received over 50 cm of new snow between Tuesday night and Wednesday afternoon.

Roughly 80-120 cm of snow is now sitting on a crust that extends up to 1900 m. In isolated areas below treeline, this recent snow may be sitting on a weak layer of surface hoar.

The main feature we are monitoring in the snowpack is a layer of weak faceted snow over a hard melt-freeze crust found around 120-200 cm down. Recent sporadic, large, naturally triggered avalanches have occurred on this layer on large alpine slopes and were triggered by either smaller wind slab avalanches, or cornice falls.

Terrain and Travel

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Avoid freshly wind loaded terrain features.
  • Minimize exposure to steep, sun exposed slopes, especially when the solar radiation is strong.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Avalanche Problems

Storm Slabs

Over 50 cm of recent snow with ongoing strong wind continues to form fresh storm and wind slabs in the region. These will likely be the most reactive in leeward terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Persistent Slabs

The recent storm added a big load to a deeply buried weak layer. Avalanches triggered on this layer will likely be large and destructive.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 3