Avalanche Forecast

Issued: Dec 29th, 2016 4:35PM

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

grant statham, Avalanche Canada

Little Yoho.

We are in a storm period and expect natural avalanches running over the next 24-48 hours. Ice climbers in Field should avoid the big gully climbs over the next few days and let this new snow settle. Skiers - wind slabs are primed for triggering.

Summary

Weather Forecast

Strong westerly flow continues but the main pulse of snowfall should taper by Friday morning. Friday looks like a mix of sun and clouds with winds tapering slightly and temperatures remaining cool (below -10). Another round of snow is expected for Saturday.

Snowpack Summary

At 1850 m. 40 cm of settled storm snow sits on the Dec 19 layer of facets and produces moderate (PC) compression test results. Another profile at 2100 m. showed no shears in the snowpack. At the higher elevations, strong winds over the past week have created widespread wind slabs which will be easily triggered by people.

Avalanche Summary

Poor visibility today, but the ski areas reported only small soft slabs within the recent snow inside the ski area boundary.

Confidence

Due to the number of field observations

Problems

Persistent Slabs

Wind slabs up to 60cm from last week sit on top of a weak layer of facets (Dec 19 layer). This interface is poorly bonded, resulting in many recent avalanches. This weak, faceted layer will persist for some time.

Be aware of the potential for wide propagations due to the presence of hard windslabs.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Thick wind slabs have formed in the lees of alpine features. These will be touchy in the short term with the current snow and wind forecast. Once initiated, they may trigger a persistent slab on the Dec.19th facets.

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Loose Dry

ICE CLIMBERS - watch out for large sluff in gullied routes as there is a lot of loose snow being blow around by the wind.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 30th, 2016 4:00PM