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

Avalanche Forecast

Mar 5th, 2013–Mar 6th, 2013
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.

Large skier triggered avalanches are still possible after last week's storm.  Steep solar aspects appear to be most reactive, and prudent route selection is advised in all locations.  Be aware of the effects of solar radiation and cornice failures.

Weather Forecast

A weak upper ridge lingers over the area today, bringing occasional sunny breaks and rising freezing levels.  Another low pressure is expected to move in on Wednesday, with moderate SW winds and moderate precipitation (up to 10 cm).  Another ridge is expected for Thursday.

Snowpack Summary

60+ cm of storm snow overlies a variety of old surfaces.  Although the storm snow is settling, it is still failing as a cohesive slab, especially on solar aspects where it sits on a sun crust.  The Feb 12 PWL is down over one meter, and remains a concern.  This layer can still be triggered by heavy loads, or as a step-down from storm snow releases.

Avalanche Summary

Natural avalanche activity has tapered off, but human triggered avalanches remain likely in specific terrain.  Yesterday, skiers triggered a size 3 avalanche on a west aspect in the alpine.  It failed less than a meter from their skis, and propagated 150 m wide, running to valley bottom.  It likely ran on a sun crust interface.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Wednesday

Avalanche Problems

Storm Slabs

Over 80cm of snow has fallen since Friday. Weak interfaces within the storm slab exist. The snowpack needs time to adjust to the new load. It will still be touchy to human triggering, and may step down to surface hoar below.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.Avoid regrouping in runout zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 2 - 3

Persistent Slabs

A weak surface hoar layer is now down ~1m. This layer has caused widespread avalanches: natural's up to size 4, and size 2.5 human triggered avalanches. In areas where it has not already avalanched it remains touchy, and has been remotely triggered.
Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 4

Wind Slabs

Wind slabs and large cornices have formed in the alpine.  Cornices are huge and should be given a wide berth.
Be cautious as you transition into wind affected terrain.Avoid steep slopes below cornices.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3