Avalanche Forecast

Issued: Nov 24th, 2018 3:43PM

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

Avalanche Canada cgarritty, Avalanche Canada

A combo of lingering wind slabs and weak basal layers affects the alpine while rugged early season conditions prevail at lower elevations.

Summary

Confidence

Moderate -

Weather Forecast

Saturday night: Mainly cloudy with light west winds.Sunday: Cloudy with sunny periods. Light southwest winds. Alpine high temperatures around -5.Monday: Cloudy with scattered flurries bringing a trace to 5 cm of new snow. Wet flurries at lower elevations. Mainly light southwest winds, increasing overnight. Alpine high temperatures around -1 as freezing levels rise to about 1600 metres.Tuesday: Cloudy with continuing flurries bringing about 5 cm of new snow. Wet flurries at lower elevations. Light to moderate southwest winds. Alpine high temperatures around -1 with freezing levels to 1700 metres.

Avalanche Summary

Skiers and explosives have recently triggered small wind slabs in cross-loaded and lee terrain features at treeline and alpine elevations. Earlier in the month, a natural avalanche cycle took place over the late October crust/facet combination. Be aware of the continued possibility for smaller avalanches to 'step down' or even initiate at this deeper layer. It exists primarily in the alpine.

Snowpack Summary

Light snowfall over Thursday and Friday buried a widespread layer of weak, feathery surface hoar crystals with about 5-10 cm of new snow. On steeper solar aspects, this surface hoar layer may instead exist as a thin sun crust below the storm snow. Reports from several points in the region show this variable layer sitting above a layer of recently reactive wind slab. This wind slab layer overlies yet another widespread layer of surface hoar from mid-November, now found about 20-40 cm deep. A final, prominent feature of the snowpack is a combination of a melt-freeze crust and underlying sugary, faceted snow found around the base of the snowpack. Avalanches have been triggered where there is a slab above this crust.

Problems

Wind Slabs

An icon showing Wind Slabs
Recently formed wind slabs may remain reactive to human triggering. Older, stubborn wind slabs may also be obscured by more recent snowfall.
Examine slopes for patterns of snow transport as you enter wind-exposed terrain.Be careful around wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
A nasty combination of crust and sugary, faceted snow exists at the base of the snowpack in the alpine. This weak layer has already produced large avalanches and may be triggered by the weight of a person, machine, or wind slab release.
Be highly suspicious of slopes that show signs of previous avalanching.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Nov 25th, 2018 2:00PM

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