Avalanche Forecast

Archived

Apr 6th, 2023–Apr 7th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Maligne, Marmot, Miette Lake, Pyramid.

Warmer weather than we've had for a while, and weak overnight freezes are forecasted for the next couple days. Signs of instability like pinwheeling or small loose wet avalanches are a good indicator that the avalanche hazard is increasing.

Confidence

Moderate

Avalanche Summary

Only isolated small loose dry avalanches in steep alpine terrain have been observed in the region in the last few days.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

Moderate to strong winds have redistributed the dusting of new snow from last week. Under this there is a sun crust at all elevations on solar aspects, with mixed facets on polar aspects. The mid-pack consists of multiple layers of dense wind effected snow, sun crusts, and facets. Depth hoar and basal facets make up the base of the snowpack. Snow depth varies ranges from 60-170cm.

Weather Summary

An upper-level southwesterly flow will bring flurries into Jasper by Friday afternoon, with minimal accumulations. Southwesterly ridgetop winds 30 to 50km/h with freezing levels rising to between 2000 and 2300m. Alpine highs range from -2°C to 2°C.

Terrain and Travel Advice

If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
Use caution on large alpine slopes, especially around thin areas that may propagate to deeper instabilities.

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.

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.

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.