Avalanche Forecast

Issued: Mar 5th, 2017 4:00PM

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

jonas hoke, Parks Canada

Waterton Lakes.

As the new snow continues to pile up, great skiing can be found almost everywhere. It seems hard to justify venturing into bigger, consequential terrain.

Summary

Weather Forecast

Monday: Cloudy. Light snowfall. Ridgetop winds Moderate SW. Alpine Temps High -11, Low -16.Tuesday: Mix of Sun and Cloud. Afternoon Flurries. Ridgetop winds Moderate trending Light SW. Alpine Temps High -10, Low -17.Wednesday: Cloudy. Snow (5-10cm). Ridgetop winds Moderate-Strong SW. Alpine Temps High -10, Low -14.

Snowpack Summary

The recent trend of snowfall and wind continues. Currently 14cm of low density snow overlies several layers of previous wind and storm slabs. A persistent weak layer of facets on a crust or old wind slabs is now down 60-90cm. Where this layer is a crust/facet combo (most likely on Sunny aspects at Treeline), the slab sitting above will be touchy.

Avalanche Summary

As recently as Saturday, large wind and storm slab avalanches have been observed as a result of natural triggers in the alpine and at treeline, these occurred primarily on N and E (lee) aspects. Last Thursday at Treeline, a small (Size 1) persistent slab was accidentally triggered by a skier, on a steep, south facing, cross-loaded slope,

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Storm Slabs

Fresh Storm Slabs will likely form this week with snow and moderate wind in the forecast.

The new snow will require several days to settle and stabilize.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

New snow may be hiding Wind Slabs formed by previous South West winds. Don't be surprised! Transition carefully into any open terrain.

Avoid steep lee and cross-loaded featuresAssess start zones carefully and use safe travel techniques.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

There is uncertainty about the distribution of this layer, it is suspected to be most reactive at Treeline, on steep S and SW aspects where facets overlie a crust.

Carefully evaluate terrain features by digging and testing on adjacent, safe slopes. Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Mar 8th, 2017 4:00PM