Avalanche Forecast
Regions: Glacier.
Warm temperatures are expected to produce large avalanches, avoid avalanche terrain.
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 9°C, light winds, FZL 3500m
Sat: sunny skies, Alp high 12°C, light southwest winds, FZL 3600m
Sun: mix of sun and cloud w/ isolated rain showers, Alp high 14°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.
Avalanche 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