Avalanche Forecast

Issued: Feb 10th, 2017 4:19PM

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

mark herbison, Parks Canada

Jasper.

Avalanche Control along the Icefields Parkway is planned for Friday 1100 - 1700, expect delays.Strong winds and 20cm+ of snow have created dangerous avalanche conditions.

Summary

Weather Forecast

The storm has ended but periods of light snow can be expected over the weekend. Alpine temps are forecasted to drop to -16 overnight and with a high of -12. Winds will be blowing moderate from the SW, gusting to strong. Temps will gradually rise until mid next week.

Snowpack Summary

30-40cm of snow within the past 36hrs with moderate to strong SW winds is building slab at treeline and above. A reactive storm slab can be found at all elevations and aspects. The upper snow pack has several touchy surface hoar and facet layers which are now buried 40-50cm and 60-80cm. The mid-pack is facetted and weak, with depth hoar at its base

Avalanche Summary

A widespread Na cycle up to Sz 2.5 on all aspects and elevations today along the Parkway. Poor visibility into the high alpine.While accessing a short and steep slope adjacent to the highway, an avalanche technician triggered the storm slab resulting in a full burial with no injuries.

Confidence

Wind speed and direction is uncertain on Saturday

Problems

Storm Slabs

30-40cm of storm snow with warming temps has promoted fast settlement, forming a touchy storm slab.

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Use caution in alpine and open treeline lees. Recent snowfall has created storm slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Wind Slabs

Moderate to strong SW winds building windslab with recent storm snow and expected to bond poorly.

Use caution in lee areas. Recent wind loading have created wind slabs.Keep an eye out for reverse loading created by an upslope storm.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Persistent Slabs

Avalanches initiated within the storm snow were stepping down to deeper layers and in some cases gouging to ground in thin snowpack areas.

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Feb 11th, 2017 4:00PM