Avalanche Forecast

Issued: Mar 10th, 2012 10:02AM

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

Avalanche Canada pgoddard, Avalanche Canada

Conditions are very tricky. There is real potential to trigger surprisingly large avalanches. Traveling in avalanche terrain right now requires an advanced skill-set.

Summary

Confidence

Fair - Timing of incoming weather is uncertain

Weather Forecast

Two cold fronts bring mainly light precipitation to the area. The exact timing of these fronts is uncertain, but the general pattern will be for mixed weather.Sunday: 5-10cm snow, falling as rain below about 1400m and getting drier as you go east. Strong south-westerly winds. Cooling as the front passes.Monday: Light convective precipitation. Mild daytime temperatures and some sunshine. Light to moderate south-westerly winds. Tuesday: Light to moderate precipitation and moderate south-westerly winds.

Avalanche Summary

A widespread natural avalanche cycle occurred up to size 3 in response to very warm temperatures and loading of start zones by strong winds on Friday and Saturday. Over the past few days, there have been several reports from in or near the region of near misses, including a snowmobiler who triggered an avalanche and was buried for around 30 minutes, remote-triggered avalanches, and slab avalanches running into unusually low-angled terrain. On Saturday, a snowmobiler was killed in an avalanche south-east of Sparwood. Details here: http://bit.ly/zMjK39

Snowpack Summary

Warming , wind-loading and cornice fall have recently caused natural avalanches, with touchy persistent weak layers in the upper snowpack increasing their size and consequence. 20-50cm of recent storm snow has become moist on solar aspects, and on all aspects at low elevations.The mid February surface hoar layer is now down between 40 & 100cm and is more prevalent in the west and south of the region, particularly in the Flathead. Recent snowpack tests as well as a rider-triggered avalanche on this weak layer indicate that it still has the potential to be triggered in many areas and if it is triggered, a large avalanche could result. Remote-triggering, triggering from below and triggering on low-angled terrain are also concerns. Lingering concern remains for basal facets, particularly in shallower snowpack areas with steep, rocky start zones. Cornices have grown large and threaten slopes below.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent strong winds have set up touchy wind slabs behind ridges and terrain breaks.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 6

Storm Slabs

An icon showing Storm Slabs
Continuing warm temperatures may prolong the current natural slab avalanche cycle.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 6

Persistent Slabs

An icon showing Persistent Slabs
A prominent persistent weak layer from the middle of February exists in some areas, and is most prevalent in the Flathead range. If triggered, this layer has the potential to produce large and dangerous avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

3 - 7

Valid until: Mar 11th, 2012 9:00AM