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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.
Below Treeline
Natural avalanches unlikely.

Regions

Glacier.

Rider triggering of the Nov 17 persistent weak layer is possible. Pay attention to signs of instability, including whumphing, cracking and settlements.

Snowpack variability and limited observations are making forecasting danger challenging, please post a MIN with any relevant observation from your backcountry travel.

Confidence

Low

Avalanche Summary

Few natural avalanche avalanches have been observed along the highway corridor in the last 3 days.

One MIN report of 'whumpfing' and remote triggering several avalanches up to size 1.5, ~50cm deep, on moraine features below Glacier Crest on Monday. A Parks Canada field team experienced widespread 'whumpfing' at treeline and below in the Fidelity area on Monday as well.

Snowpack Summary

5-10 cm of fresh storm snow on Wednesday with light winds. This overlies wind slabs in alpine and treeline lee features built by strong SW winds. The Nov 17 persistent slab (surface hoar 5-30mm, facets, and crust) is down 70-90cm with the largest surface hoar present at treeline and below.

The early season hazards are slowly being buried but remain a concern. The height of snow at treeline is ~140cm.

Weather Summary

As a storm exits the region Thursday morning, isolated flurries linger and cold temperatures return through Saturday.

Thursday expect a mix of sun and cloud, possible flurries, an Alpine high of -14*C, light NW ridge-top winds.

Fri/Sat isolated flurries are forecast with mod to light SW ridge top winds and Alpine highs of -15*C.

More details can be found in the Mountain Weather Forecast.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • Recent new snow may be hiding windslabs that were easily visible before the snow fell.

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.

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.