Avalanche Forecast

Issued: Nov 26th, 2019 4:00PM

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

Avalanche Canada mconlan, Avalanche Canada

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A cold, windy day is forecast for Wednesday. Wind slabs may overly several weak layers.

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

TUESDAY NIGHT: Cloudy with light snowfall, accumulation 2 to 5 cm, light to moderate east wind, alpine temperature -15 C, freezing level below valley bottom.

WEDNESDAY: Mostly cloudy with light snowfall, accumulation 1 to 3 cm, moderate to strong east wind, alpine temperature -17 C, freezing level below valley bottom.

THURSDAY: Clear skies, light northeast wind, alpine temperature -16 C, freezing level below valley bottom.

FRIDAY: Clear skies, light northeast wind, alpine temperature -14 C, freezing level below valley bottom.

Avalanche Summary

We've received reports of a skier and explosives triggering avalanches on north facing alpine terrain in the past few days.

If you see anything while out in the field, please consider sharing that information with us and fellow recreationists via the Mountain Information Network (MIN).

Snowpack Summary

Around 10 to 30 cm of recent snow may overly a weak layer of feathery surface hoar. The distribution of the surface hoar is currently not well understood. The recent snow may get blown around on Wednesday with strong wind from the northeast, forming wind slabs at higher elevations.

Spatial variability is large right now, with the snowpack depth ranging from 10 cm to 100 cm. Expect to find weak and faceted snow in the thin areas. Elsewhere, you may find a potentially problematic melt-freeze crust from late October above faceted snow near the base of the snowpack.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs may form on all aspects due to wind that started from the west and switched to the east. These slabs could be particularly touchy where they overly a weak layer of surface hoar that formed last week.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

A melt-freeze crust and sugary faceted grains exist in the lower snowpack. There is uncertainty with how reactive this layer may be (as described here). With this uncertainty, it is best to recreate conservatively, be on high alert, and conduct your own assessments throughout the day.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Nov 27th, 2019 5:00PM