Avalanche Forecast

Issued: Mar 5th, 2016 4:00PM

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

deryl kelly, Parks Canada

Jasper.

The layer of facets, decomposing stellars and surface hoar down 40-70cms making it very difficult to predict the sensitivity of the persistent slab with field tests. Progressive decision from low angle to steep terrain is key for safe riding.

Summary

Weather Forecast

Light scattered flurries throughout the weekend, up to 6 to 8cm by Sunday evening. Temperatures to remain cool above treeline and freezing levels rising to 2000ms over the day Sunday. Winds expected to be in the lower moderate range from the Southwest.

Snowpack Summary

Continued building wind slab in lee and cross-loaded terrain above 2000m. A persistent weakness down 40-70cm is stubborn but can be triggered underfoot, especially in shallow areas. Snowpack is facetted at lower elevations and the base is extremely weak. Large triggers such as cornice fall or other avalanches will likely trigger this weakness.

Avalanche Summary

Field reports of solar triggered slab avalanches in the alpine and treeline in wind loaded areas up to size 3 in the Maligne area. Scoured areas, beside loaded features are obvious and we can't stress enough diligent decision making and general avoidance of these weaker and shallow areas .

Confidence

Due to the number of field observations

Problems

Persistent Slabs

Persistent weak layers of some combination of decomposed surface hoar, facets, and depth hoar in many locations. These layers have been stubborn to trigger underfoot but will be triggered by cornice failure or from shallow spot and release to ground.

Carefully evaluate terrain features by digging and testing on adjacent, safe slopes. Avoid steep slopes below cornices.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

Expect slab development immediate to lee ridge lines and cross loaded features. Bonding should be suspect, progress cautiously into steeper terrain.

Be cautious as you transition into wind affected terrain.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 6th, 2016 4:00PM