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Avalanche Forecast

Archived

May 2nd, 2023–May 4th, 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

Banff Yoho Kootenay, Little Yoho, Banff, East Side 93N, Kootenay, Lake Louise, LLSA, Sunshine, West Side 93N, Field.

The hot weather will continue through the week, with alpine temperatures reaching +15 and freezing levels to 4000 m. Avoid all avalanche terrain. Backcountry conditions are poor and will not improve until it cools later this week. Hikers and scramblers: avoid all avalanche terrain.

Confidence

High

Avalanche Summary

A widespread natural avalanche cycle to size 4 continues with avalanches failing on the ground level on all aspects and elevations, many running to the valley bottom. This is the biggest avalanche cycle of the season. Click the link's for recent avalanche info on the Plain of Six Glaciers and Lake Louise area.

Snowpack Summary

The heat has penetrated the snowpack and destabilized it at all elevations. Warm temperatures overnight will prevent any refreezing. This will persist for the remainder of this week. Expect wet snow on all solar aspects and unsupportive isothermal snow (slush) at lower elevations. Widespread avalanches are failing on the ground.

Weather Summary

A ridge of high pressure will continue to dominate the region over the next few days bringing unseasonably hot weather, sunny skies and light winds. Freezing levels may reach 4000 m. Clouds and cooling should arrive by next weekend.

Terrain and Travel Advice

  • Avoid all avalanche terrain during periods of intense solar radiation.
  • Avoid exposure to overhead avalanche terrain as temperatures increase.

Problems

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.

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.

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.