Avalanche Forecast

Issued: Feb 24th, 2015 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.

matt.mueller, Alberta Parks

Kananaskis.

As we approach spring, remember that the sun can have a very rapid warming effect on snow. Cornices, wind slabs and loose surface snow can easily fail when exposed to rapid warming.

Summary

Confidence

Good

Weather Forecast

Mostly cloudy with convective cells moving through. Only trace amounts expected. Light winds at ridge top, gusting to 45km/hr. Alpine high of -8. Valley bottom freezing level. We are at the time of year when any solar exposure can have a dramatic and sudden effect on the snow surface. It is also very difficult to forecast for these sunny periods. Watch for sun exposed places, and treat accordingly.

Avalanche Summary

A natural cornice sz 2.5, 2600m, NE aspect, initiated in steep cliffs and entrained snow below. There was widespread pin wheeling and loose wet avalanches from yesterday afternoon's heat. Average size was 1, with a few scattered 1.5's.

Snowpack Summary

Despite yesterday's high of 5 degrees, the snow held in there. We escaped another temperature crust and are left with a new crust on all solar aspects. This new sun crust extends well into the alpine. Valley bottom travel is reasonable with the older breakable crust down only a few cm's. At treeline, northerly aspects still have dry snow with some wind effect in open areas. The alpine has been hit with winds and is mostly breakable windslab on lee aspects (NE-S).

Problems

Persistent Slabs

Steep, convex terrain near ridge crests still pose a concern. Investigate bigger terrain carefully before committing.

Caution in lee and cross-loaded terrain near ridge crests.>

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Deep Persistent Slabs

Large triggers have recently impacted this layer in variable depth terrain. Watch for a weak snowpack in alpine areas and anticipate where the thin areas might be. Probing is a valuable tool to figure out snow depth trends.

Be aware of thin areas that may propogate to deeper instabilites.>Carefully evaluate and use caution around thin snowpack areas.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 5

Valid until: Feb 25th, 2015 2:00PM