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Avalanche Forecast

Feb 12th, 2013–Feb 13th, 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
1: Low
The avalanche danger rating below treeline will be low
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
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Jasper.

Select your line conservatively, since the best turns for the next few days will be on soft slabs that will not bond well to the old, hard wind hammered snow surface.

Weather Forecast

A system is moving through overnight with moderate to strong SW winds that will create windslabs on lee ridgetops and terrain features. The anticipated snowfall is around 10 - 20cm in the icefields area and less as you go further North toward jasper. A trailing cold front will drop the temperature and the skies are expected to clear late Wednesday.

Snowpack Summary

Hard windslab is bridging the weak basal facets above treeline.  Field tests on Monday in the alpine on a SE windloaded terrain feature produced easy results on a buried surface hoar layer directly below the hardslab. This confirms that there are several weak layers below that the avalanche can slide on.  Below treeline, the mid-pack is weak.

Avalanche Summary

No new avalanches were observed today.

Confidence

Forecast snowfall amounts are uncertain on Wednesday

Avalanche Problems

Wind Slabs

Moderate to strong Southwest winds beginning today in the icefields will create windslabs from the 10 - 20cm snowfall expected overnight. This  will load lee terrain features.
Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.Avoid freshly wind loaded features.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

The hard windslabs that dominate the alpine snowpack have been unreactive lately. It still may be possible to trigger an avalanche on steep unsupported terrain from thin areas and the edges of these slabs.
Avoid convexities or areas with a thin or variable snowpack.

Aspects: North, North East, East, South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 1 - 3