Avalanche Forecast

Issued: Jan 5th, 2012 8:13AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs, Persistent Slabs and Deep Persistent Slabs.

sylvia forest, Parks Canada

Glacier.

Avalanche control is occurring today. Grizzly is the only permit area open. Large avalanches overnight (to size 3.5) have run to the end of the run out zones and into creeks. Extreme winds (S 145) and wet precipitation has created unstable slabs.

Summary

Problems

Storm Slabs

A rain crust that formed on Jan 3 is buried by 30cm of moist storm snow. Very high South winds (40-145 kph) and mild temps (+1C) have created a storm slab over this crust, which is now very reactive, producing large avalanches to valley bottom.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 4

Persistent Slabs

The Dec. 11 SH layer is still evident in the snowpack. Although becoming less reactive, large triggers such as cornice failures and avalanches are stepping down to this weakness. Recent avalanche activity has stepped down to this layer overnight.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Deep Persistent Slabs

In the high alpine basal weaknesses exist and may cause large or very large avalanches. These may slide from large triggers or during periods of heavy storm loading. Large glide cracks failing near ground are also a significant concern this year.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 4

Valid until: Jan 6th, 2012 8:00AM