Avalanche Forecast

Issued: Mar 27th, 2016 3:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Persistent Slabs and Deep Persistent Slabs.

Alberta Parks mike.koppang, Alberta Parks

A  storm is forecated overnight but snowfall amounts are uncertain.  If fsnowfalls are significant i.e. >10cm we can expect avalanche danger to return to Considerable.  Cloudy skies are forecast so the solar influence should be minimal on Monday.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Monday

Weather Forecast

Forecast models differ.  One says we may see up to 15cm of snow from an upslope storm coming through the region while the other says only a few cm's.  If we do get the higher amounts forecasted we can expect avalanche danger to return to considerable at treeline and above!  Winds are forecast to increase out of the Sw into the moderate range overnight with a freezing level near 1900m.

Avalanche Summary

A few loose wet slides up to sz 1 were observed later in the day on Sunday.

Snowpack Summary

In the am, the surface crust was holding together pretty well with overnight lows of -10C at 2200m.  This crust is up to 20cm on solar aspects but it was fully broken down on these aspects by later in the day due to the solar radiation.  Expect to encounter a melt freeze crust on all aspects up to 2200m then the only place you wont find the crust will be on true north aspects.  The base of the snowpack still consists of weak facetted crystals that are the foundation of the stronger upper snowpack layers.  Thin shallow snowpack areas remain the most likely places to trigger a failure in these basal crystals that may propagate out into deeper areas.  Solar radiation is having a strong influence on the stability right now.  Expect stability to decrease as temperatures warm up throughout the day.  These decreases will be most apparent on solar aspects especially where the snowpack is shallow.  Cornices are also large and have been failing with the heat so be sure to keep and eye on these features.

Problems

Persistent Slabs

An icon showing Persistent Slabs
Persistent slabs have been forming from the new over the past week. These slabs are overlying the 0321 melt freeze crust on solar aspects and previous windslabs on northern aspects.
Avoid steep, open slopes.>Avoid lee and cross-loaded terrain near ridge crests.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Basal facets and the Jan 6th interface are likely to be triggered from thinner snowpack areas.
Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.>Stick to non-avalanche terrain or small features with limited consequence.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 6

Valid until: Mar 28th, 2016 2:00PM

Login