Avalanche Forecast

Issued: Jan 20th, 2014 8:43AM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.

Avalanche Canada bcorrigan, Avalanche Canada

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

A strong ridge of high pressure continues to dominate the weather in BC and eastern Alberta, with no significant precipitation in sight for the next week. A temperature inversion will raise temps at upper elevations and bring valley cloud to most of the area. Daytime heating will raise valley temps, but freezing levels should drop to valley bottom each night.Tuesday and Wednesday freezing levels will rise to 1400 metres in the forecast area with a possibility of flurries for Wednesday. Winds light from the west for most of the forecast period.

Avalanche Summary

No reports of recent avalanche activity in the forecast region, although sluffing continues in steep terrain, snowballing and pinwheel activity on steep solar aspects during the warmest parts of the day.

Snowpack Summary

Wind continues to redistribute surface snow throughout the region. The snowpack varies widely, but appears to be deeper in the north and east. Basal facets continue to be a concern where wind slabs and storm slabs have added load above these weak layers. The forecast very warm alpine temperatures may result in periods of rapid warming in the wind and storm slabs above weak layers. Strong solar radiation may cause moist or wet loose snow avalanches or cornice falls in the alpine resulting in large additional loads above deeply buried weak layers. Surface hoar has been reported forming on protected north and east slopes along with facetting of the surface and storm slab in protected locations. Solar aspects have begun forming sun crust in some locations.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs continue to grow on lee slopes at tree line and above. In some areas these slabs may be up to one metre thick. Warm temperatures may result in loose wet avalanches on southerly aspects, or cornice falls, triggering deeper instabilities.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Avoid shallow snowpack areas where triggering is more likely.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
Storm snow may not bond to the surface hoar and melt-freeze crusts that developed before the storm. Storm slabs are more likely in areas sheltered from the recent strong winds. Forecast warm temperatures may result in easier triggering of these slabs
Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
This problem is more likely in areas that had a shallow snowpack during the cold arctic outbreak. Loose wet avalanches or cornice falls may trigger deeply buried weak layers resulting in large destructive avalanches.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Avoid lingering in runout zones.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Jan 21st, 2014 2:00PM

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