Archived

Avalanche Forecast

Dec 14th, 2015–Dec 15th, 2015

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Kootenay Boundary.

Wind slabs on North AND South facing slopes... ...on account of shifting winds. Watch for the potential for mostly small avalanches on steep exposed terrain.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

On Tuesday and Wednesday: a few light flurries, mostly light winds from the north and freezing levels at valley bottom. On Thursday: winds will shift round to the south in anticipation of an approaching storm, but at this point, the models don't have snowfall starting until Thursday evening. Freezing level remains at valley bottom.

Avalanche Summary

Over the weekend, size 1 and size 2 avalanches could be triggered by skiers and explosive avalanche testing in the newly deposited storm snow on north aspects between 1900 and 2100 m. I anticipate avalanches will become harder to trigger as the storm snow settles and temperatures drop.

Snowpack Summary

20-50 cm recent snowfall sits over a thick rain crust. Reports indicate wind loading occurred on north aspects during the storm and then subsequently on southern aspects as the wind shifted around to the north. The crust in the upper snowpack can be found as high as 2400m. At treeline elevation it is thick and supportive, and should be capping any deeper weaknesses. The weak layer from early December has recently become inactive, likely due to all the moisture in the snowpack and subsequent settlement and re-freezing.

Avalanche Problems

Wind Slabs

Wind loading occurred initially on north-facing slopes and with a switch to northerly winds, on slopes facing south.

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

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3