Avalanche Forecast

Issued: Apr 7th, 2016 8:08AM

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

danyelle magnan, Parks Canada

Glacier.

The snowpack is very weak due to continued warm temps. Over the next few days strong sun and very warm temperatures will cause danger to rise quickly. It sure feels like summer; maybe it's time to consider pulling out your bike or rock shoes?

Summary

Weather Forecast

Today and Friday are forecast to be sunny and very warm! Freezing levels are expected to rise as high as 3500m, with alpine temps in the shade reaching 10'C. Add the sun to that and it will feel tropical. Temps are expected to stay above freezing overnight, so even an early start won't help on Friday. By Sat we should get an overnight recovery.

Snowpack Summary

At treeline and above a ~30cm storm slab overlies a 3 cm thick crust. Below the crust the upper ~70cm of snow is warm, moist and weak. Sustained S'ly winds at ridgetop will have built deeper, more cohesive slabs on lee and cross-loaded slopes. At 1300m the surface crust that formed overnight is only 3cm thick with a very weak overnight recovery.

Avalanche Summary

Yesterday a skier triggered a size 2.5 on the headwall of Youngs Peak; a W aspect at ~2675m. The avalanche was 20-80cm deep and ran 150m. Luckily the skier was not buried. In addition a few loose wet natural avalanches, mostly size 2 but one size 3, were observed running into valley bottoms.

Confidence

Problems

Loose Wet

The snowpack is generally warm and weak; we have yet to undergo a true melt-freeze cycle due to ongoing warm overnight temps. Strong solar and very warm temps are forecast and loose wet avalanches are expected.

Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Storm Slabs

A ~30cm deep storm slab has developed and sits on a crust. Sustained winds will have built deeper pockets on lee slopes and in cross-loaded areas. These are likely to exist in areas where skiers/boarders are searching for skiable snow.

Use caution in lee areas in the alpine and treeline. Storm snow is forming touchy slabs.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Huge cornices along ridges will be weakened by the strong sun today and continued above freezing temps. A chunk of cornice tumbling down-slope is a concern in itself, but cornices failures also provide a heavy trigger and may trigger large avalanches

Cornices become weak with daytime heating, so travel early on exposed slopes.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Apr 8th, 2016 8:00AM