Avalanche Forecast

Issued: Dec 30th, 2016 8:00AM

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

percy woods, Parks Canada

Glacier.

Conservative route selection is advised. Watch for signs of slab formation especially in wind exposed terrain.

Summary

Weather Forecast

Mainly cloudy with isolated flurries. Alpine temperature of -11C and ridge top west winds in the 15-25km/h. The trend is toward clearing and cooling temperatures as high pressure moves in to start 2017.

Snowpack Summary

50cm of storm snow in 2 days, mod S winds at ridgetop should be building reactive wind slab in the alpine along with storm slab formation at all 3 elevation levels. Several weak layers were observed yesterday as the storm snow settles into a slab. Dec 18th facet/surface hoar layer should not be discounted and may wake with this extra load.

Avalanche Summary

Earlier in the week we had skiers report sensitive wind slab on SW aspect at 2100m on McGill. Now we have 50cm more snow load. Avalanche control east of the pass this morning is producing slides in the size 3 range.

Confidence

Due to the number of field observations

Problems

Storm Slabs

50cm storm snow in 48hrs with flurries expected today. The storm snow has buried a spotty surface hoar layer to dig and look for. The new load will take a few days to stabilize.

The new snow will require several days to settle and stabilize.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Wind Slabs

50cm of storm snow in 48hrs. The snowfall has been accompanied by moderate gusting to strong S winds has built a fresh reactive windslab in the alpine that has potential for wide propagation.

Watch for whumpfing, hollow sounds, and shooting cracks.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Valid until: Dec 31st, 2016 8:00AM