Avalanche Forecast

Issued: Dec 17th, 2018 4:00PM

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

adam greenberg, Parks Canada

Waterton Lakes.

Another storm is set to hit us on Tuesday. This may be the tipping point that overloads weak layers on the bottom of the snowpack.

Summary

Weather Forecast

Tuesday: Periods of snow beginning Monday night with 16 cm of accumulation along the divide accompanied by strong west winds. Freezing levels Staying near 1600m.Wednesday: Cloudy with scattered flurries. Moderate SW winds. Freezing level 1400mThursday: Cloudy with sunny periods. Moderate SW winds Freezing levels returning to 1600m

Snowpack Summary

The snowpack in Waterton is highly variable, but you can count on a weaker structure along the divide where 20-30cm of recent storm snow has formed windslabs on lee (east) slopes which are sitting on a weak snowpack consisting of facets and crusts.

Avalanche Summary

Natural and human triggered avalanche activity has tapered off, with no new avalanches observed in the region. Warm weather has caused pinwheeling on Solar aspects.

Confidence

Freezing levels are uncertain on Thursday

Problems

Wind Slabs

Old windslabs to be bonding well to old surfaces thanks to warm temperatures, but a new set will be forming with the incoming storm on Tuesday.

If triggered the wind slabs may step down to deeper layers resulting in larger avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

New snow will increase the load on deep weak layers. We may see the same kind of cycle that our norther neighbours saw last week.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Dec 20th, 2018 4:00PM