Avalanche Forecast

Issued: Mar 24th, 2014 8:00AM

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

Parks Canada ali haeri, Parks Canada

Solar radiation this morning is expected to be cut out by cloud cover but a thin layer of cloud could increase the solar affect. Manage your groups exposure to overhead hazard accordingly.

Summary

Weather Forecast

Weakening ridge of high pressure over the interior will mean increasing cloudiness today. No precipitation is expected until Tuesday night when a Pacific system makes it way over to us. Light to moderate amounts are expected then with rising freezing levels,.

Snowpack Summary

The upper snowpack will vary depending on aspect. North and east will have settling snow, south and west will have the Mar 22 crust down 10cm. The Mar 13 crust down 45-65 and the March 2 CR/SH layer down 1m. Tests show hard sudden result on the Mar 2 layer, propagation tests still show large potential for propagation. The Feb10 layer is down ~2m.

Avalanche Summary

No new avalanches yesterday observed or reported in the park yesterday. On Friday a size 3.5 natural avalanche released in Grizzly Bowl, SE asp, ~2600m, presumably from a cornice trigger. These sporadic events keep our guard up.

Confidence

Intensity of incoming weather systems is uncertain on Wednesday

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slab instabilities newly formed soft slab in the lee of ridge crests may exist and pop with human triggering.
Be cautious as you transition into wind affected terrain.Caution in lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
Snowpack tests yesterday show the Mar 2 layer down ~1m to still be reactive with large consequences if triggered. Shallow snowpack areas, like slopes that have lots of rocks poking out, seem to be the most likely areas for this to happen.
Avoid shallow snowpack areas where triggering is more likely.Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Another deep weakness in the snow pack is the February surface hoar/crust layer. Large triggers, such as a cornice fall or a running avalanche, will be needed to step down to this layer.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

3 - 4

Valid until: Mar 25th, 2014 8:00AM