Avalanche Forecast

Archived

Nov 30th, 2022–Dec 1st, 2022

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

A complex persistent weak layer exists down 30-40cm consisting of surface hoar and or facets, and a solar crust on southerly aspects. If you choose to brave the cold temperatures, pay attention to signs of instability such as cracking and whumpfing, and dig to assess this layer before commiting to avalanche terrain.

Confidence

Moderate

Avalanche Summary

Field team in the Icefield area on Monday observed shooting cracks and whumpfing on surface hoar layer down 30 cm at tree line and below in sheltered east to northerly aspects. Nov 27th MIN report confirms the presence of the same layer of concern in the Maligne region. Marmot Ski Area reporting no recent results from explosive testing and control.

Snowpack Summary

5cm new snow on Thursday fell on 25-35cm of low density facetted snow. Below this is a layer of concern comprised of surface hoar/facets in sheltered locations treeline and below, and a solar crust on southerly aspects. The surface hoar/facet layer may extend into isolated alpine terrain. Strength of the lower snowpack deteriorating with recent persistent cold temperatures. Height of snow ranges from 60 to 100cm.

Weather Summary

The Arctic ridge of high pressure will reassert itself Thursday with clear, cold, and dry conditions persisting through the weekend. Variable light winds will increase to moderate values from the southwest late Friday.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
Back off if you encounter whumpfing, hollow sounds, or shooting cracks.

Problems

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.