Avalanche Forecast

Issued: Dec 9th, 2017 4:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Loose Dry and Deep Persistent Slabs.

a.l. horton, Parks Canada

Jasper.

The avalanche danger will rise on Monday as the freezing level rises to 3500m.

Summary

Weather Forecast

Strong Westerly winds beginning overnight and continuing through the day. Freezing level 1600m. Alpine temperature -4 . Starting Sunday evening, the temperature will rise through the day on Monday with the freezing level reaching 3500m. Temperatures cool on Tuesday. No precipitation is expected......

Snowpack Summary

Melt freeze crust on steep solar aspects treeline and above. There is a well settled snowpack in most locations. A 30 - 70 cm thick slab overlies a crust and bonding appears to be strengthening at this interface. The Halloween Oct 31 crust sits near the bottom of the snowpack from treeline to 2700 m.

Avalanche Summary

No patrol occurred on Saturday and nothing new was reported. A helicopter flight on Thursday observed numerous dry loose avalanches, size 1-2, along the Icefields Parkway and Maligne Lake Road on steep solar aspects, running to treeline. One size 3 slab avalanche was noted on a steep South facing slope that ran on the Halloween Crust to treeline.

Confidence

Freezing levels are uncertain on Sunday

Problems

Loose Dry

Solar triggering of loose avalanches may occur in steep terrain. The entraining snow may have enough volume to knock ice climbers off or bury you in a terrain trap. Reactivity increases with afternoon sun.

Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Deep Persistent Slabs

Solar triggering is possible on steep south facing slopes.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Dec 10th, 2017 4:00PM