Avalanche Forecast

Issued: Dec 5th, 2017 4:30PM

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 cgarritty, Avalanche Canada

Change is in the air with strong solar effect and the beginning of a warming trend in the forecast. These two factors will begin to undermine stability on Wednesday.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

Wednesday: A mix of sun and cloud. Light northwest winds. Alpine temperatures around -3 and rising in the afternoon and evening with the onset of an alpine temperature inversion.Thursday: Mainly sunny with some valley cloud. Freezing level rising from 2700 to 3300 metres over the day with a strong temperature inversion. Alpine temperatures to about +5 with cooler temperatures at lower elevations.Friday: Sunny. Light west winds. Freezing level remaining around 3300 metres with alpine temperatures to about +7. Cooler at lower elevations under the lingering temperature inversion.

Avalanche Summary

No new avalanches have been reported from this region. There is potential for triggering wind slabs on leeward slopes and dry loose avalanches from steeper terrain features. Smaller avalanches may also step down and trigger larger avalanches on buried weak layers deeper in the snowpack. Please submit your observations to the Mountain Information Network.

Snowpack Summary

Average snowpack depths at upper elevations in the region range from 60-110 cm. Snow surfaces have been scoured on southwesterly slopes and deeper pockets of wind slab likely exist on northeasterly slopes. Below the surface, the two crusts that were buried near the end of November can now be found approximately 40 cm and 70 cm down. Deeper in the snowpack a third crust from the end of October exists as a "facet/crust" combo and has been identified as a potential sliding interface. Snowpack testing in the adjacent Kananaskis Country forecast region has yielded hard but sudden results on this layer.

Problems

Wind Slabs

An icon showing Wind Slabs
Stiff wind slabs could be reactive to rider triggers at treeline and in the alpine on leeward and cross-loaded slopes. Be especially cautious of cross-loaded slopes that see sun exposure on Wednesday.
Watch for whumpfing, hollow sounds, and shooting cracks.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
There are several crusts now buried within the snowpack. Use extra caution in thin snowpack areas where it may be possible to trigger a deeper layer. Triggering a wind slab may also have the potential to step-down to a deeper layer.
If triggered, wind slabs may step down to deeper layers and result in large avalanches.Be aware of triggering thin areas that may propagate to deep instabilites more easily.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Dec 6th, 2017 2:00PM