Avalanche Forecast

Issued: Apr 3rd, 2016 9:22AM

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

pgoddard, Avalanche Canada

South Rockies.

Conditions are expected to change during the day. The loose wet avalanche cycle should taper off with cooling temperatures, but glide slabs and persistent slabs may continue to fail.

Summary

Confidence

Moderate - Freezing levels are uncertain on Monday

Weather Forecast

A front passing through on Monday is expected to bring cloud, light precipitation and moderate to strong SW winds, with the freezing level falling from around 2700 m to 1800 m. Cloud and a few snow showers may linger on Tuesday morning, before a ridge brings dry and very warm weather again.

Avalanche Summary

A cycle of large natural avalanches has been reported from the north Elk Valley, which occurred on Friday and Saturday. At least one of these appears to be a persistent slab, and all were likely to have been triggered by warming. A size 2.5 storm slab also released in steep rocky terrain in the south-east on Friday. Although temperatures are expected to cool on Monday night, they shoot right back up after that. The cycle may continue...

Snowpack Summary

Large cornices overhang alpine slopes. Glide cracks have opened up on several slopes and herald more glide avalanches to come. Recent storm snow (which was deepest in the south-east) has settled with continued warm temperatures. Crusts which have been forming at the surface by night have been breaking down quickly by day and low elevation and thin snowpack areas have become isothermal. Deeply buried weak layers in the mid snowpack and near the ground appear to have woken up in some areas with prolonged warming (see avalanche discussion).

Problems

Cornices

Large fragile cornices threaten many slopes. A cornice fall could wake up a persistent weak layer and trigger a large avalanche on the slope below.

Do not travel on slopes that are exposed to cornices overhead.>Stay well to the windward side of corniced ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Persistent Slabs

Prolonged warming has reawakened deeply buried weak layers, as well as causing glide slabs to release at the ground. The result is some surprisingly large avalanches.

Avoid slopes with glide cracks.>Choose conservative lines and plan to regroup out of avalanche terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Apr 4th, 2016 2:00PM