Register
Get forecast notifications
Create an account to receive email notifications when forecasts are published.
Login
Archived

Avalanche Forecast

Nov 21st, 2020–Nov 22nd, 2020
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Glacier.

Do not let good visibility and great skiing entice you to ski bigger lines.  The Nov. 5th crust/facet persistent weak layer is ripe for catching skiers off guard.

Weather Forecast

Unsettled air will give mostly cloudy skies and isolated flurries through the weekend.  A system making landfall from the NW Monday and will give snowfall early in the week.

Today: Alpine High -8 °C. Ridge wind(RW) light SW. Freezing level (FzL): 1100m.

Tonight: Low -9 °C. RW light S.

Sunday: High -5 °C. RW Light. FzL: 1200m.

Snowpack Summary

Up to 70cm of storm snow and Southwesterly winds has formed reactive slabs. The Nov 5th crust is now down buried over 1m deep in most starting zones. This crust is 8cm thick, and can be found up to 2500m on all aspects. Facets above and below the crust are making this combo an active weak layer that will persist for the foreseeable future.

Avalanche Summary

Large natural avalanches continue to occur as ongoing snowfall and wind progressively overloads the snowpack. These are generally initiating in the storm snow, with some stepping down to the Nov 5th crust/facet combo. There were several Min reports this week of natural, and skier triggered avalanches, as well as large whumphs in open terrain.

Confidence

Avalanche Problems

Persistent Slabs

Steep open slopes should be avoided.  Snowpack tests, and reports of whumphs from yesterday, indicate that this layer could still be triggered by the weight of a skier.

  • Be aware of the potential for wide propagations which could result in large avalanches.
  • Minimize exposure to overhead avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 2 - 3.5

Storm Slabs

Recent new snow and Southwesterly winds have created storm slabs in the alpine, and exposed areas of treeline. Natural avalanches are possible today and skier triggering remains likely, especially on steep unsupported terrain features.

  • Convex features and steep unsupported slopes will be most prone to triggering.
  • If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1.5 - 3