Avalanche Forecast

Issued: Mar 29th, 2014 9:17AM

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

mbender, Avalanche Canada

South Rockies.

Summary

Confidence

Poor - Forecast snowfall amounts are uncertain on Sunday

Weather Forecast

Sunday: Cloudy with light to moderate snowfall possible. Light southerly winds. Freezing level 1500m.Monday: Mix of sun and cloud with possible intermittent flurries. Light west winds. Freezing level 1500m.Tuesday: Mainly sunny with some cloudy periods. Light westerly winds. Freezing level 1800m.

Avalanche Summary

Recent observations are limited to loose snow avalanches running in steep terrain to size 1.5 at all elevations.

Snowpack Summary

See this great video from our South Rockies field team that does an awesome job of summarizing the current state of the snowpack.Up to 25cm of recent new snow sits on top of a thick sun crust on solar aspects. 70-90 cm of settling storm snow from the past week rests on a graupel layer that can be found in much of the region. This makes for around 90 cm on top of the mid march crust at this point. This crust exists on all aspects below 2000m and on solar aspects in the high alpine. North of Sparwood and in the Crowsnest Pass area, the buried crust seems more specific to previously sun-exposed slopes. The deep facet/crust persistent weakness buried at the beginning of February (now down up to 150cm) seems unlikely to trigger in areas where the hard, supportive crust exists. No matter where you are in the region, this weakness should stay on your radar as any activity at this interface would be large and destructive. Possible triggers include a large cornice fall, a large input in a thin snowpack area or solar warming.

Problems

Wind Slabs

Moderate southwest and more recent west winds have created wind slabs in the lee of terrain features.

Use ridges or ribs to avoid pockets of wind loaded snow.>Be cautious of sluffing in steep terrain.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

The deep weak layers that formed in early February may be a bit touchier in the north of the region. Possible triggers at this point include a large cornice fall, surface avalanche in motion or solar warming.

Consider the consequences of the terrain if an avalanche steps down to a persistent weakness.>Caution around convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Mar 30th, 2014 2:00PM