Avalanche Forecast

Issued: Dec 29th, 2015 8:35AM

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

triley, Avalanche Canada

South Rockies.

Wind slabs continue to be a concern at higher elevations. In some areas wind slabs may be sitting on a weak layer of facetted snow.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

Mostly clear overnight. Clear on Wednesday with a chance of some valley cloud remaining below about 1500 metres. Alpine temperatures around -15 overnight and rising up to about -10 during the day with light northerly winds. Clear overnight Wednesday and Thursday. Alpine temperatures around -23 Thursday morning, warming to around -10 on Thursday afternoon with light westerly winds. The inversion should be well developed by Friday, with clear skies and alpine temperatures around -5.

Avalanche Summary

On Sunday a group of sledders triggered or remotely triggered a slab avalanche size 2.0 about 2km south of Castle Mountain that resulted in one rider deploying his airbag and being partially buried. See the MIN report for more information.

Snowpack Summary

Our field team was in the Smith Basin and Mirror Lakes area on Monday. They reported 110-150 cm of snow on the ground at 2250 metres. There was 40 cm of loose dry snow above 10 cm of cold facets that produced variable moderate to hard shears in snowpack tests. The storm snow is unconsolidated and the field team remarked that even the small larch trees still had new snow on them; evidence of very little in the way of wind. They did not get direct alpine observations, but suspect that there may be more wind effect at higher elevations. These observations are consistent with reports from near Castle Mountain with storm snow above facets.

Problems

Wind Slabs

Wind slabs continue to be a problem where the recent storm was transported into deep pockets. In some areas these wind slabs may be stiff and may also be sitting on a weak layer of cold faceted snow.

Avoid travelling in areas that have been reverse loaded by winds.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

New cornice growth may fragile and easily triggered by traveling nearby.

Give cornices a wide berth when travelling on or below ridges.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 30th, 2015 2:00PM