Avalanche Forecast

Issued: Dec 26th, 2013 4:00PM

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

max darrah, Parks Canada

Jasper.

A shallow snowpack, deep persistent slab and basal weakness have created a tricky start to the season - conservative route selection and avoidance of big terrain in the alpine is advised. Have a safe and happy holiday season!

Summary

Weather Forecast

Mild temperatures through to Friday evening, at which point they are expected to drop back to more seasonal norms (-10C at 2100m). Southwest flow will continue to dominate with generally light to moderate values, gusting to high in the alpine. Minimal precipitation is expected - models predict 0-5cm over the next 24 hours. Freezing level 1400m.

Snowpack Summary

No significant precipitation over the last week (1mm in past 72 hours / 5mm past 7 days). Snowpack is generally shallow, weak, with a variably distributed deep persistent slab overlying weak basal layers of depth hoar, crusts, and/or facets. A steady southwest flow has created pockets of windslab in exposed areas at treeline and above.

Avalanche Summary

1 new natural slab avalanche observed today in the alpine on a Southwest aspect - size 2. Likely ran on basal weakness. Numerous natural slab avalanches to size 2.5 observed in the past week, primarily on cross loaded gully features in the alpine.

Confidence

Problems

Deep Persistent Slabs

Currently there is a variably distributed persistent slab in a generally shallow snowpack. Although stubborn, if this slab is triggered it will result in a full depth avalanche running on weak layers at or near the bottom of the snowpack.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.Avoid steep, open slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

Steady Southwest winds have created pockets of windslab on lee features above treeline. Recent natural activity has been observed in crossloaded gully features in the alpine.

Be careful with wind loaded pockets. Be aware of wide variation in snowpack depthCaution in lee and cross-loaded terrain near ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 27th, 2013 4:00PM