Avalanche Forecast

Issued: Mar 23rd, 2013 9:29AM

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

jfloyer, Avalanche Canada

South Rockies.

Summary

Confidence

Good

Weather Forecast

Synopsis: Generally very fine weather with cool overnight temperatures and warm, sunny days.Sunday, Monday and Tuesday: Clear and sunny. Freezing level around 1800 m, becoming slightly higher each day. Light winds.

Avalanche Summary

A couple of large natural avalanches were reported from northeast of Sparwood that likely ran on Wednesday or Thursday on the buried rain crust. On Friday, a few cornice releases were observed and sluffing was noted in the new snow on steep terrain.

Snowpack Summary

Approximately 40-70 cm recent storm snow sits on top of a buried rain crust that exists up to around 2100 m. In areas near Sparwood, the new snow initially bonded poorly to this crust, and a few large avalanches were observed that likely released on this layer. In the North Elk Valley, the bond at the crust was reported to be good. Generally, this interface has now become stronger for all parts of the region, and is now considered unlikely to release due to the weight of a person alone. However, a large trigger, such as a cornice fall, or an airborne sledder, could potentially trigger a large avalanche on this layer in steep terrain. Recent wind slabs exist in the immediate lee of ridge lines and terrain features. Cornices are large and fragile. Mid and lower snowpack layers are generally well-settled.

Problems

Cornices

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

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 5

Wind Slabs

Wind loaded and cross-loaded slopes can still be found at treeline and alpine elevations. There is still a chance a small wind slab avalanche could step down to the March 16th rain crust.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Avoid steep slopes with convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Loose Wet

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 24th, 2013 2:00PM