Avalanche Forecast

Issued: Nov 27th, 2017 4:57PM

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

Avalanche Canada jmcbride, Avalanche Canada

With winter's return keep an eye out for new wind slabs and be extra cautious in thin snowpack areas where it may be possible to trigger a deeper layer in the snowpack. And if you do have any observations be sure to share them on the MIN.

Summary

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

Tuesday: Flurries, accumulation 5-10 cm. Moderate to strong southwest wind. Alpine temperature near -7. Freezing level 1100 m.Wednesday: Mix of sun and cloud. Moderate west wind. Alpine temperature near -7. Freezing level 1000 m.Thursday: Cloudy, isolated flurries. Moderate to strong west wind. Alpine temperature near -7. Freezing level 1000 m.

Avalanche Summary

There have been no reports of avalanche activity in the region since last week's natural, wet cycle during the big rain event. To the north however, Kananaskis Country reports persistent slab activity to Size 2.5 initiating on layers at or near the base of the snowpack in the alpine and running to treeline. While natural avalanche activity is likely to taper off with a return to cooler temperatures and lowering freezing levels, new snow and wind are creating wind slabs in alpine lee areas. Once initiated, the possibility of a slab release stepping down to a deeper layer within the snowpack still exists.

Snowpack Summary

Sunday brought more rain and light snowfall amounts to upper elevations across the region. The southern part of the region received about 5 cm overnight while northern areas saw as much as 10-15 cm at 2200 m and above. While there is little information regarding snowpack structure, snowpack depths vary from 40-60 cm at 1800 m elevation to 80-100 cm near 2300m. Several crusts are expected to exist within the snowpack including the most recent rain crust which is now buried by 10-30 cm of new snow. Below this crust lies the Halloween crust as well as the early October rain crust at the base of the snowpack.

Problems

Wind Slabs

An icon showing Wind Slabs
Watch for wind-transported, pillowy snow on leeward and cross-loaded slopes.
Use caution in lee areas. New snow and wind loading may have created wind slabs.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
There are several crusts now buried within the snowpack. Be extra caution in thin snowpack areas where it may be possible to trigger these layers and assume that a release near the surface may also have the potential to step-down to a deeper layer.
Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Nov 28th, 2017 2:00PM