Avalanche Forecast

Issued: Jan 26th, 2018 4:16PM

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

Tim Haggarty, Parks Canada

Jasper.

Avalanche control work today on Parker Ridge today confirmed that triggering a large slab with a light load is quite possible. With isolated natural activity observed today as well, it is clear that the stakes are starting to rise...

Summary

Weather Forecast

Saturday will see continued cool temps with cloud and the potential for light flurries. On Sunday a SW flow will bring 5-10cm of precipitation with winds increasing to moderate SW and temperatures rising into the -10C range.. Significant snow may arrive Monday as temps peak at -5 C in the alpine.

Snowpack Summary

Persistent slabs sit above 3 weak interfaces in the top 30 to 50cm of the snowpack. Depth and distribution of these weak surface hoar/facet layers varies with the terrain and vegetation shelter, but they are consistently found in sheltered features at TL and above. Windslabs have developed in open areas TL.

Avalanche Summary

Natural windslab avalanches up to size 1.5 were observed Tuesday in windswept alpine moraine features. These events appeared to be running on the persistent slab interface down 30 to 50cm.

Confidence

Intensity of incoming weather systems is uncertain on Sunday

Problems

Persistent Slabs

This problem is made up of 3 significant interfaces in the top 30-50cm of the snowpack and deeper in isolated wind loaded locations. These slabs have been active to skier testing and explosive control work producing a few very significant results.

Watch for whumpfing, hollow sounds, and shooting cracks.Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Wind Slabs

Last week's storm snow with southwesterly winds has built soft slabs in open features. These were reactive Thursday, failing as small sluffs out of cliff terrain hit the slope.

Be cautious as you transition into wind affected terrain.Be careful with wind loaded pockets while approaching and climbing ice routes.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 27th, 2018 4:00PM