Avalanche Forecast

Issued: Feb 9th, 2017 4:08PM

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

Avalanche Canada cgarritty, Avalanche Canada

A Special Public Avalanche Warning applies to this region.

Summary

Confidence

High -

Weather Forecast

FRIDAY: Scattered flurries, accumulation 5cm / Moderate to strong west wind / Alpine temperature -8SATURDAY: Mix of sun and cloud / Moderate west wind / Alpine temperature -11SUNDAY: Cloudy with isolated flurries / Moderate west wind / Alpine temperature -7More details can be found on the Mountain Weather Forecast.

Avalanche Summary

On Thursday there was a report of a size 2.5 natural avalanche 50-120cm deep on a NW aspect in Waterton Park. Expect the recent dense storm slab to be reactive to human triggering in the coming days as the all the new snow from the past 10 days starts to settle. Storm slab avalanches have the potential to step down to the basal weakness which would drastically increase the size and destructive potential of a resulting avalanche.

Snowpack Summary

Thursday saw 15-30cm of moist new snow fall on top of the 90cm of low density storm snow that accumulated last weekend. Strong shifting winds have redistributed the previous storm's snow in exposed terrain forming touchy wind slabs. These wind slabs are now obscured by the latest blanket of snow. All this overlies a highly variable old surface which may include wind affected surfaces, facets, and/or a rain crust below around 1500 m. Recent reports suggest a poor bond between the storms' snow and the old surface. In deeper areas, the snowpack appears to be well settled with isolated concerns about the mid-December facet layer which was buried 50-100 cm deep prior to the weekend storm. In shallow snowpack areas and at lower elevations, the snowpack is weak, faceted, and has no structure. Prior to the storm, it was possible to step onto the snow surface in these areas and sink right to the ground.

Problems

Storm Slabs

An icon showing Storm Slabs
Additional new snow, warmer temperatures and wind have created touchy new moist storm and wind slabs
Use conservative route selection, choose low angled and supported terrain with low consequence.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
A weak layer at the bottom of the snowpack is creating the potential for full depth avalanche releases. Storm slab avalanches have the potential to step down to this layer. This is most likely in the thin snowpack areas of the region.
Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.If triggered the storm slabs may step down to deeper layers resulting in very large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Feb 10th, 2017 2:00PM