Avalanche Forecast

Archived

May 1st, 2022–May 2nd, 2022

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Glacier.

We are headed into an 'all melt- no freeze' state over the next few days.

Be sure your exit plan manages your exposure to solar slopes. Afternoon avalanche danger ratings could reach CONSIDERABLE tomorrow.

Weather Forecast

Limited overnight crust recovery with alpine temperature inversions.

Tonight: Mainly cloudy. Alpine low 1*C, freezing level (fzl) 1800m. Light south wind.

Mon: Mix sun and cloud. High 4*C, fzl 2500m. Wind light SE.

Tues: Mainly sunny. Low 1*C, High 4*C, fzl 2700m

Wed: Mix sun and cloud with isolated wet flurries. Low 0*C, High 3*C, fzl 2800m.

Snowpack Summary

We have 2 distinct snowpacks.

Below treeline the spring-time melt-freeze snowpack is solid in the morning, and breaks down with daytime warming.

In the Alpine, on N'ly slopes you'll find a more winterlike snowpack with settled dry powder, and variable crusty surfaces on solar aspects.

Cornices are large and looming.

Avalanche Summary

Numerous large (size 2-2.5) loose wet avalanches occurred today from all aspects in steep paths along the highway corridor. There was also a notable very large (size 3) cornice release in the Grizzly highway path. Most of these avalanches are entraining surface snow only, but a couple steep S'ly paths are starting to see some gouging deeper.

Confidence

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.

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.