Archived

Avalanche Forecast

Feb 20th, 2012–Feb 21st, 2012

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Kananaskis.

The Valentine's layers of surface hoar/facets/sun crust are now buried 30 to 45cm and are highly sensitive to human triggering. Several skier remote and skier accidental avalanches have occurred over the past 48 hours.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Wednesday

Weather Forecast

Avalanche Summary

Num sluffs to size 1.5 from steep ALP terrain on N and E asp.Sev Na slabs up to size 2.,5 2200m to 2700m, mostly N and E asp. Suspect 120213 as failure plane.! size 2.0 slab triggered by skiers cutting out a chunk of cornice and rolling it down hill on SE asp at 2500m. Chunk rolled approx 100m and triggered a slab 45cm deep X 25m wide X 300m long.2 Sr size 2.0 and 1.5 reported yesterday in Hero's knob area from NE asp in ALP1 Sa size 1.0 reported yesterday from Hero's knob area in BTL terrain.

Snowpack Summary

5 to 7cm Hn. Total of 30 to 45cm over Valentine's layers. Wind affect ALP and variable wind affect TL and BTL.

Avalanche Problems

Wind Slabs

Wind slab development is ongoing and numerous natural and skier triggered avalanches have occurred in the past 48 hours. These slabs are between 30 and 45cm deep and are highly sensitive to human triggering. Remote triggering is a concern.

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

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 5

Loose Dry

Loose unconsolidated surface snow is sluffing in steep terrain producing avalanches up to size 1.5. Skier traffic produces sluffing in steep terrain that could gain enough mass to be concerning.

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

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 4

Deep Persistent Slabs

Weak facets and depth hoar linger at the base of the snowpack. Thin steep areas are the most likely trigger points. This problem is still a low probability issue, but with high potential consequences.

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 6