Avalanche Forecast

Issued: Jan 30th, 2012 9:36AM

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

Avalanche Canada jlammers, Avalanche Canada

If you're heading into the Bonnington Range, please see our Forecast Details page for specific snowpack information.

Summary

Confidence

Fair - Freezing levels are uncertain on Thursday

Weather Forecast

Tuesday: light snowfall / light southwest winds / freezing level at 900mWednesday: light snowfall in the morning with clearing by the afternoon / light southwest winds / freezing level at 900mThursday: mostly clear / light northwest winds / freezing level climbing throughout the day to 1200m

Avalanche Summary

Numerous fresh windslab avalanches to size 2 were observed in the region on Sunday. Expect continued windslab avalanche activity in wind-affected terrain in the wake of Sunday night's wind, snow and moderate temperatures.More deep activity was reported from the Bonnington Range on Saturday where a size 2.5 and a size 3 avalanche were reported to have released on the mid-December surface hoar/facet layer.

Snowpack Summary

Warmer temperatures, moderate southwest winds and moderate snowfall on Sunday night has added to an ongoing wind slab issue creating cohesive and reactive wind slabs at treeline and in the alpine. In some parts of the region underlying storm snow from mid-week is sitting on 1 or 2 freezing rain crusts that developed on Tuesday morning. Reactivity on the crust (which sits about 45cm below the surface in most wind-neutral areas) has become unlikely. A few operators are also talking about a surface hoar layer that was buried on January 14th. Its reactivity has been described as "stubborn", but it has potential to size 3. A layer of concern deeper in the snowpack is the surface hoar/facet layer from mid-December. This layer has become less of a concern in the vast majority of locations. In the Bonnington Range, however, it is still on the radar of backcountry travelers as the layer is still reactive and is producing avalanches to size 3 in isolated features. This lingering layer of concern reflects the variability of the snowpack within the region. Snowpack depths in the region are around 230 cm at treeline.

Problems

Wind Slabs

An icon showing Wind Slabs
Windslabs have set up in the lee of exposed features at treeline and in the alpine.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Storm Slabs

An icon showing Storm Slabs
Recent snowfall has added to the current storm slab problem. Watch for storm slabs on steeper, unsupported features

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Jan 31st, 2012 8:00AM

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