Avalanche Forecast

Issued: Dec 11th, 2018 3:08PM

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

michael.olsthoorn, Alberta Parks

Kananaskis.

HEADS UP!!A storm is to bring 15-30cm with up to 90km/hr winds in the alpine. This will create extensive wind slabs sitting on a weak base. Perfect recipe for avalanches.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Wednesday

Weather Forecast

Big change on its way. We are expected to have 10-15cm of new snow by Wednesday morning with additional amounts of 5-15cm during the day on Wednesday. The big kicker is that the winds will be strong from the west. We are talking of winds up to 90km/hr. Temperatures will be steady around -10c.

Avalanche Summary

No recent avalanches were observed on Tuesday Dec 11. We are likely to see some with this storm coming.

Snowpack Summary

The strong westerly winds have been blowing since Monday morning. On Tuesday, these winds were fairly constant in the 70km/hr range. The few cm of snow that has fallen on Tuesday with whatever was kicking around has now turned into widespread wind slabs in the alpine and at tree line. With the 10-15cm of snow forecast by Wednesday morning and the strong west winds, expect extensive wind slab development on all exposed slopes. More snow and 90km/hr winds for Wednesday will continue to grow the wind slabs. Expect these new slabs to be touchy and if they do release, they will probably step down into the weak base layers and involve the whole snowpack.

Problems

Deep Persistent Slabs

This storm is expected to bring up to 30cm of snow with continued strong westerly winds. Potential for full snowpack failure with these new wind slabs.

Minimize overhead exposure during periods of heavy loading from new snow, wind.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

Strong winds since Monday along with the forecast snow and winds will create extensive wind slabs.

Be aware of the potential for wide propagations due to the presence of hard windslabs.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.