Avalanche Forecast

Issued: Jan 27th, 2016 4:00PM

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

jonas hoke, Parks Canada

Waterton Lakes.

The potential for buried persistent weak layers to have created a low probability/high consequence avalanche problem makes for decreased confidence. Evaluate the snowpack and terrain carefully before exposing yourself to larger features.

Summary

Weather Forecast

Ongoing chinook winds (strong to extreme from the west) and warm temperatures (highs of 10 deg for the townsite and freezing levels as high as 2100m) will begin to abate Thursday afternoon, as the trailing end of a cold front brings increasing cloudiness, cooling temperatures and light precipitation to the area through Friday.

Snowpack Summary

Strong to extreme chinook (westerly) winds continue to build windslabs in lees and windpressed surfaces in exposed areas. These windslabs are stubborn to trigger but may propagate widely if they initiate on/step down to previously buried weak layers; a Jan 4th crust/surface hoar (solar/shady aspects) down 40-70cm, and a Dec 9th crust down 70-120cm.

Avalanche Summary

A few isolated large avalanches were observed locally last weekend, these are suspected to have been persistent slabs failing on the Jan 4 crust/surface hoar layer. Neighboring ski operations have been reporting isolated large persistent slab avalanches failing on the Dec. 9th crust.

Confidence

Freezing levels are uncertain

Problems

Wind Slabs

While stubborn to trigger, windslabs have the potential step down to previously buried weak layers.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Avoid steep lee and cross-loaded slopes

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

A weak layers buried in early January and early December have not been ruled out as the potential failure plane of several large, recent slab avalanches. While the probability of triggering these layers is low, the consequences will be significant.

Assess start zones carefully and use safe travel techniques.Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

1 - 3

Loose Wet

Use caution above cliffs where small avalanches may have severe consequences.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1

Valid until: Jan 30th, 2016 4:00PM