Avalanche Forecast

Issued: Mar 11th, 2013 3:00PM

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

Alberta Parks burke.duncan, Alberta Parks

Warm, moist air pushing in to the region from the SW will bring with it an increase in Avalanche Danger by midweek.  The new snow will be sitting on top a a variety of old surface layers ranging form sun crusts to soft and hard windslabs.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Tuesday

Weather Forecast

A SW flow beginning early Tuesday is forecast to bring with it strong to extreme winds, up to 30mm of precipitation by Thursday AM and rising temperatures - a classic setup for increasing Avalanche Danger.

Avalanche Summary

A few loose dry from steep lee terrain.

Snowpack Summary

In open alpine terrain expect to encounter soft slabs, hard slabs and sastrugi due to widespread wind effects. Sheltered areas that have been shaded offer loose dry snow while solar aspects sport a mix of variable crusts.

Problems

Wind Slabs

An icon showing Wind Slabs
Winds Sunday resulted in rapid loading with redistribution of the storm snow. Soft slabs at TL & ALP were approaching the reactive level in specific areas. The bond with the existing slab interfaces needs to be carefully assessed.
Avoid convexities or areas with a thin or variable snowpack.>Avoid areas with overhead hazard.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
This layer (Feb HSL) has been a suspected failure plain in a number of avalanches lately. A fresh sz2 on Little Tent Ridge was observed at TL elev in skiable terrain.
Avoid exposure to overhead avalanche terrain, as large avalanches may reach the end of runout zones.>Avoid freshly wind loaded features.>Avoid runouts where triggering slopes from below is possible.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Mar 12th, 2013 2:00PM