Avalanche Forecast

Issued: Apr 6th, 2017 8:10AM

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

danyelle magnan, Parks Canada

Glacier.

Look up! If cornices threaten your route adjust your plan. Cornice failures are hard to predict and are the likely trigger for very large avalanches. Although sporadic, these avalanches have been very destructive.

Summary

Weather Forecast

Today freezing levels will be around 2000m with flurries in the alpine and rain at treeline and below. Overnight freezing levels will drop and provide a weak overnight recovery. On Fri, freezing levels will rise back up to 1800m with up to 20cm expected in the alpine, and rain at lower elevations. Sat flurries continue with freezing levels at 1400m

Snowpack Summary

~30cm soft slab sits on a crust that exists everywhere other than N aspects above 1800m. Below 1900m this slab is being saturated by rain. The upper snowpack is a complex mix of crusts and spotty surface hoar layers. Deeper in the snowpack, old persistent weak layers that include crusts and facets have been reactive to large triggers like cornices

Avalanche Summary

High elevation N aspects hold dry snow that sluffs easily with skier traffic. Natural avalanche activity has been sporadic, but very large avalanches continue to be reported in the region daily. Cornices or smaller avalanches have been triggering deep persistent layers. At lower elevations, wet snow on crusts are expected to be reactive.

Confidence

Timing of incoming weather systems is uncertain

Problems

Persistent Slabs

Soft slabs overlie a series of strong crusts in most areas. As freezing levels rise this slab is expected to be increasingly reactive. These slabs will be deepest in areas that have been wind-loaded.

Choose well supported terrain without convexities.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Cornices

Huge cornices loom at ridgetop and have been failing unpredictably. When they drop they provide large triggers for deep, persistent weak layers. The resulting avalanches have been observed to run well into the valley bottoms.

Avoid travel on slopes that are exposed to cornices overhead.Minimize exposure to overhead avalanche terrain, large avalanches are reaching run out zones.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Loose Wet

At treeline and below, rain is saturating the snow that overlies a series of crusts. This wet snow will be easily triggered, is expected to run far on the crust and even if small, wet avalanches are powerful.

Use safe ski cutting techniques before entering ski run. Ski short pitches and regroup in safe spots.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 7th, 2017 8:00AM