Avalanche Forecast

Issued: Nov 22nd, 2017 8:06AM

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

Parks Canada percy woods, Parks Canada

The atmospheric river of warm moisture is upon us.  Look for an avalanche danger increasing to HIGH later today.

Summary

Weather Forecast

Wet flurries Mod SW wind gusting to strong, and freezing level bumping up to 2900m later today. Temperatures are already above freezing at Round Hill station at 2100m. The forecast atmospheric river is upon us and will bring high freezing levels, moderate to strong SW winds and heavy precipitation into Thursday afternoon.

Snowpack Summary

Warm temps and a mix of rain and snow are destabilizing surface layers in the snowpack. Last weekend's storm snow will be settling rapidly. Mod shears in the storm snow down 40cm and 60cm at 2000m yesterday. The Oct 31st crust down 100cm should awaken in the next 48hrs.

Avalanche Summary

One new size 2 avalanche recorded yesterday in the highway corridor. Expecting an avalanche cycle to start on Wednesday and continue into the afternoon on Thursday.

Confidence

Timing of incoming weather systems is uncertain

Problems

Storm Slabs

An icon showing Storm Slabs
Last weekend's storm slab will be settling quickly. Weak layers down 40cm and 60cm and Nov 9th interface should awaken with rapid warming, increased precipitation and strong SW winds forecast today.
Use conservative route selection, choose moderate angled and supported terrain with low consequence.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Warm temperatures and continued loading should be enough to awaken the Oct 31st crust over the next 48hrs. The question is timing which may be later today or into Thursday morning.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Nov 23rd, 2017 8:00AM