Avalanche Forecast

Issued: Apr 5th, 2013 8:00AM

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

jon schleiss, Parks Canada

Glacier.

Warm wet new snow and rain overnight, and warming temperatures have combined to create increasing avalanche danger.

Summary

Weather Forecast

A low pressure system sits over the Selkirk mountains, bringing warm temperatures and locally moderate to heavy precipitation. Winds will be moderate from the SW. Freezing levels will be around 2000m today.

Snowpack Summary

Moist snow and rain overnight with snow sticking to the trees at about 1600m elevation this morning. Heavy wet new snow over an isothermal snowpack has been reported from a treeline observatory, and avalanche activity can be expected today.

Avalanche Summary

A few natural avalanches were reported yesterday, from size 2-3. Many recent glide crack avalanches.Numerous loose wet avalanches to size 3.0 in the backcountry on solar aspects over the last week.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Loose Wet

Rain and heavy wet new snow will cause avalanche triggering in the upper layers of the snow pack. Avalanches that trigger on a shallow crust can dig deeper into the isothermal snow and get bigger.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Deep Persistent Slabs

Glide cracks, gaping cracks in the snowpack, exist on many slopes and have been failing with the warm temps. They can fail unpredictably, and release the entire snowpack to the ground and can be triggered by smaller shallow avalanches.

Watch for glide cracks.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 4

Cornices

Cornices are large and unsupported. They are weak from the warm temperatures, and the warm wet new snow. If they fail, they may trigger deeper slabs.

Do not travel on slopes that are exposed to cornices overhead.Give cornices a wide berth when travelling on or below ridges.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Apr 6th, 2013 8:00AM