Avalanche Forecast

Issued: Jan 31st, 2019 4:00PM

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.

adam greenberg, Parks Canada

Waterton Lakes.

This weekends hazard hinges on snowfall amounts with anywhere between 10 to 30cm forecast. Keep an eye on how much snow actually arrives on Saturday and Sunday

Summary

Weather Forecast

Finally, some snow! An incoming system will bring 10-30cm of precipitation on Saturday and Sunday. Warm temperatures and SW winds will rapidly switch to very cold temperatures (-30 in the alpine) and E winds on saturday night. This will set up nicely for the storm to end depositing nice cold fluffy snow, with higher amounts in the front ranges.

Snowpack Summary

15-20cm settled powder has been redistributed by strong to extreme west winds in the alpine and at treeline. This sits on a variety of wind affected surfaces and a melt freeze crust below 2000m. The midpack is strong in deep snowpack areas, but the facets lingering at the bottom remain a concern in thinner areas.

Avalanche Summary

A skier controlled size 1.5 avalanche was reported on a west aspect at treeline in the Castle mountain backcountry. No recent avalanches have been observed in the forecast area.

Confidence

Intensity of incoming weather systems is uncertain on Saturday

Problems

Wind Slabs

New windslabs will be forming with the incoming storm on Saturday. As the winds switch from southwest to northeast on Saturday night, be aware of the potential for reverse loading.

Keep an eye out for reverse loading created by an upslope storm.Use caution in lee areas. Wind loading could create slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

A layer of weak facets is lurking at the bottom of the snowpack. Though there has been limited activity on this layer, it is still on our mind with consistent sudden collapse results in test profiles.

Avoid steep convexities or areas with a thin or variable snowpack.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Feb 3rd, 2019 4:00PM