Avalanche Forecast

Issued: Dec 4th, 2016 8:15AM

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

percy woods, Parks Canada

Glacier.

Conditions are ripe for natural and human triggered avalanches.

Summary

Weather Forecast

Mainly cloudy with isolated flurries amounting to a few more cm. Alpine temps cooling to -10C with NW winds light gusting to moderate.

Snowpack Summary

Upwards of 60cm of storm snow in the past 48hrs at treeline elevation. Snow was redistributed by S winds in the moderate range. Touchy windslabs were reported at 2100m above Hospital bowl on a SE aspect with cracking, whumphing and remote triggering of unsupported features at 10m distance.

Avalanche Summary

13 avalanches observed on Mt MacDonald in the highway corridor on N aspect running into the fan. 1 size 3 avalanche off S asp of Mt Tupper overnight. An MCR report noted an avalanche running 3/4 path off of Cheops yesterday afternoon.

Confidence

Forecast snowfall amounts are uncertain

Problems

Wind Slabs

Fresh windslab has formed with reports of cracking, whumphing and remote triggering possible in surface layers at and above treeline. Human triggering is occurring. Loose dry sluffing will also be an issue to contend with.

Watch for whumpfing, hollow sounds, and shooting cracks.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Storm Slabs

Newly formed storm slabs should be treated as susceptible to human triggering. Once triggered it may overload the Nov 13 crust layer resulting in large avalanches.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Dry

Upwards of 60cm of loose dry snow has fallen. Sluff management will be essential for safe travel. Watch for others above and below you. Sluffs may overload storm and windslabs given the right location.

Avoid travelling under cliffs that are exposed to sluffing from above.Avoid regrouping in runout zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 5th, 2016 8:00AM