Avalanche Forecast

Issued: Nov 21st, 2017 4:00PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is high. Known problems include Persistent Slabs, Storm Slabs and Loose Wet.

jonas hoke, Parks Canada

Jasper.

Hazard will be increasing the next few days with warm temperatures, rain, snow at higher elevations, and strong winds.

Summary

Weather Forecast

A strong moist southwest flow will drive the weather for the next few days.Tonight: 16cm of snow, with alpine lows of -4, and mod-strong SW windWednesday: 9cm of snow, alpine highs of +1, freezing level 2400m, and mod-extreme SW windThursday: 26cm of snow, alpine highs of +1 and lows of -5, freezing level 2200m, mod-extreme SW wind

Snowpack Summary

Incoming new snow, accompanied by strong winds and warm temps, will quickly form fresh slabs. These will fall on top of the 20-60cm of snow already burying the Oct 31 crust, which is a likely failure plane for persistent slab avalanches.

Avalanche Summary

A patrol on Monday's observed numerous fresh size 2's mainly at treeline but also a few noted in lower alpine locations. They ranged from 35-45 degrees, 100m wide, 20-40cm deep, and some ran down in to the runouts of larger avalanche paths. No patrol occurred on Tuesday.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Persistent Slabs

Expect incoming snow to overload the Halloween crust. This may produce our first cycle of large avalanches this season.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Storm Slabs

Total new snow accumulations may reach 60cm by Friday.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Loose Wet

The distribution of this problem will be tied to the freezing levels. Rainfall may occur up into the alpine in the coming days.

Carry avalanche safety equipment on ice climbs in avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Nov 22nd, 2017 4:00PM