Archived

Avalanche Forecast

Mar 18th, 2013–Mar 19th, 2013

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

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.

Periods of intense solar radiation are possible on Tuesday, so watch for the associated rise in avalanche danger on solar aspects. The upper snowpack is complex with several crusts. Carefully evaluate the snowpack before committing to a line.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Tuesday should bring some sunny weather, but not particularly warm temperatures. Winds are expected to be moderate from the W to NW. Another wave of warm, windy and wet weather is expected late Wednesday.

Avalanche Summary

A more isolated natural avalanche cycle continued today. Both slab and loose avalanches were observed up to size 2.0, and seemed to be confined to the storm snow.

Snowpack Summary

Between 10 and 20cm of new snow fell in the past 24hrs depending on location. Storm snow totals are now near 50cm at treeline. Reverse wind loading yesterday and "traditional" wind loading today have formed touchy storm slabs on all aspects at alpine and treeline elevations. Wind transport at ridgetop was intense at times today and some sluffing was observed in steep alpine terrain. Two separate crusts crusts buried between 50 and 100cm in the snowpack are still causing concern for a step-down avalanche.

Avalanche Problems

Storm Slabs

Storm slab formation continued today in alpine and open treeline terrain. Slabs up to 40cm thick are found on all aspects due to variable winds. In some cases the slabs sit on a crust layer. These slabs are currently sensitive to human triggering.

Be cautious as you transition into wind affected terrain.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 5

Persistent Slabs

A buried rain crust is found on all aspects up to 22-2400m. The bond with this new snow and the underlying crust is variable. Be sure to dig down and inspect this layer as you travel. Convex slopes at treeline and gullies are suspect.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be very cautious with gully features.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

Up to 80cm of recent snow is overlying the Mar 3 temperature crust that is being found on solar aspects well up into the alpine. Field tests are showing the bond of the new snow to this crust as good but warm temperatures may wake up this layer.

Avoid steep Southerly aspects.>Avoid unsupported slopes.>Be aware of thin areas that may propagate to deeper instabilites.>

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 4