Avalanche Forecast

Issued: Apr 27th, 2023 4:00PM

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

DH, Avalanche Canada

Glacier.

Warm temperatures are expected to produce large avalanches, avoid avalanche terrain.

Summary

Confidence

High

Avalanche Summary

Numerous moist/wet, loose surface avalanches have been observed throughout the week from steep terrain on all aspects at and below treeline. These point releases gather substantial mass as they move downslope into warmer snow.

Temps and FZLs will continue to climb weakening the snowpack on all aspects and elevations. Expect loose avalanches to increase in size and may step down to deep layers, possibly even the Nov 17 facets.

Snowpack Summary

Warm temperatures and very little overnight refreeze have produced a weak, moist upper snowpack at all elevations. Several crusts are buried 30-50cm but are breaking down as the snow warms up.

Below treeline the snowpack is wet and weak, 20-40cm above the ground the Nov 17 basal weakness can still be found in many areas.

Weather Summary

Warm and sunny weather will continue right through the weekend with above seasonal temperatures and high freezing levels (FZL).

Fri: sunny skies, Alp high 9Â°C, light winds, FZL 3500m

Sat: sunny skies, Alp high 12Â°C, light southwest winds, FZL 3600m

Sun: mix of sun and cloud w/ isolated rain showers, Alp high 14Â°C, light south winds, FZL 3500m.

Terrain and Travel Advice

As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.

Problems

Loose Wet

With intense solar heating and very little overnight refreeze the surface snow is moist and weak. Loose wet avalanches are easily triggered in steep terrain and can gain surprising mass.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Wet Slabs

Several buried crusts exist in the upper snowpack, the deepest of which is the Mar 31 layer. As the upper snowpack loses strength and cohesion during this intense warm up these crusts may provide a failure plane for the wet snow.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Cornices

As temperatures soar to new highs expect cornices to become weak and begin failing naturally which may also trigger large avalanches on the slopes below. These features can be surprisingly large, give sharp ridge crests a wide birth.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1.5 - 2.5

Deep Persistent Slabs

The increasing warmth is penetrating deep into the snowpack. The potential for this early season basal weakness to wake up and produce very destructive avalanches increases with each day of warming.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4.5

Valid until: Apr 28th, 2023 4:00PM