Avalanche Forecast

Issued: Dec 9th, 2014 8:35AM

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

Avalanche Canada rbuhler, Avalanche Canada

The warm, wet, windy storm continues. Backcountry ski conditions are reported to be terrible and avalanche hazard remains elevated. Now is a good time for indoor activities or take your rain gear with you to your local ski hill.

Summary

Confidence

Poor - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

The storm system continues to bring warm, wet conditions to the interior for Wednesday and Thursday. The Purcells region can expect another 5-10mm on Wednesday and 10-15mm for Thursday. Freezing levels on both days are expected to be 2200-2500m. Alpine winds should remain strong but might start to taper off late-Thursday. On a positive note, things should start to change on Friday. Freezing levels should drop, winds should ease, and we may see new snow at higher elevations.

Avalanche Summary

Limited observations on Tuesday includes a report of explosive triggered slabs up to size 1.5 in the Golden area. Also reported was small loose wet activity in the Invermere area.

Snowpack Summary

New moist or wet snowfall sits 10-20cm above a layer of surface hoar. Another 15-20cm below this you may find a hard rain crust. In the Golden area this crust exists up to around 1600m, whereas in the south it is up to 2000m or higher. In total, last week's storm produced slabs up to 1m thick in the north of the region and around 60cm thick in the south. This slab sits on the mid-November weak layer (surface hoar, facets, and/or a crust). Below this you will likely find a 15-20cm thick layer of sugary facets, which is sitting on a solid rain crust from early November. The reactivity of these layers may be slowly diminishing, but they still warrant cautious consideration. Snowpack tests are getting hard pops and drops results, indicating the potential for large propagation and large avalanches.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs will continue to build at higher elevations as the storm progresses. Strong winds will quickly reload leeward features.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Minimize overhead exposure; avalanches triggered by windloading may reach run out zones.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Likelihood of triggering a deep weak layer is expected to increase with new storm loading and warming. Any slopes that did not avalanche during the last storm cycle should still be considered hazardous. Smaller avalanches may trigger a deep release.
Choose well supported terrain without convexities.>Avoid common trigger zones including thin snowpack areas, near rocky outcrops, and steep alpine slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Loose Wet

An icon showing Loose Wet
Rain at lower elevations will reduce the stability of the upper snowpack and loose wet avalanches are expected in steep terrain.
Be cautious of sluffing in steep terrain.>Avoid areas with steep overhead hazard.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Dec 10th, 2014 2:00PM