Avalanche Forecast

Archived

May 1st, 2023–May 2nd, 2023

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Regions

Glacier.

Any avalanche start zone that still holds snow should be avoided. Wet, loose "slurpee" slop is the best way to describe the snowpack at the moment. With continued hot temps to mtn-top, stay away from all avalanche terrain!

Confidence

High

Avalanche Summary

Avalanche control from Sunday produced excellent results, with wet/loose avalanches gathering up the winter snowpack and bulldozing it down to the valley bottom. Many slidepaths failed down to ground once the avalanches reached Treeline elevations and lower.

Any start zone that still holds snow right now should be avoided!

Snowpack Summary

Warm temps and no 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 weather continues with above seasonal temps, high freezing levels (FZL), and no overnight freeze in the Alpine.

Tonight: Mostly clear, Alpine Low 10°C, FZL 3700m, Light E ridgetop wind

Tues: Mix of sun/cloud, Alpine High 14°C, FZL 3800m, light E winds

Wed: sun/cloud/isolated showers, Alpine high 14°C, FZL 3700m, light S winds

Terrain and Travel Advice

The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.

Problems

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Wet Slabs

Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.