Avalanche Forecast

Issued: Feb 24th, 2013 8:51AM

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

Avalanche Canada Peter, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Synopsis: A brief ridge of high pressure builds in for Monday bringing drier conditions and a mix of sun and cloud. The next system is forecast to affect the region on Tuesday. Monday: A mix of sun and cloud. The freezing level is around 600 m. Winds are light from the northwest.Tuesday: Light to moderate snowfall – 10-15 cm. The freezing level is around 500 m and winds increase to moderate or strong from the south-southeast. Wednesday: Unsettled with flurries or periods of snow. The freezing level is steady near 500 m and winds remain moderate from the south.

Avalanche Summary

Observations are still quite limited due to poor weather but there are a few reports of natural slab avalanches up to size 3 from treeline areas, and numerous reports of loose moist avalanches up to size 2 from steep below treeline terrain.

Snowpack Summary

The snow continues to pile up with another 25-40 cm overnight. This brings the total storm snow amounts from the past week to well over 1 m. Mild temperatures have promoted rapid settlement of the storm snow. This new snow fell on a crust, old wind slab, and/or surface hoar depending on aspect and elevation. One recent snowpack test near Shames resulted in a hard "pops" shear on the buried surface hoar, down around 60 cm at the time. Most areas are reporting that the snow has bonded well to the underlying melt-freeze crust. Cornices that now loom over many features may become weak with continued growth and/or daytime warming. The mid and lower snowpack layers are generally well settled and strong.

Problems

Storm Slabs

An icon showing Storm Slabs
It may be possible to trigger deep storm slabs in steep terrain, particularly in exposed lee and cross-loaded features (north through east facing slopes).
Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>Be cautious as you transition into wind affected terrain.>Start with lower angle slopes before gradually working up to steeper objectives.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 5

Cornices

An icon showing Cornices
Cornices have grown large and weak and may pop off with continued growth or during periods of mild sunny weather.
Give cornices a wide berth when travelling on or below ridges.>Do not travel on slopes that are exposed to cornices overhead.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Valid until: Feb 25th, 2013 2:00PM