Avalanche Forecast

Issued: Jan 28th, 2018 4:00PM

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

jonas hoke, Parks Canada

Jasper.

Ongoing snowfall will cause the hazard to build through out the day. It might be a good idea to finish your objective early.

Summary

Weather Forecast

An Atmospheric River is hitting the South Coast and giving moderate precip as far inland as Jasper. Monday: Snow, 20 cm, High -3 C Low -9 C, light gusting strong SW wind, Freezing level 1700 meters. Tuesday: Flurries, 6 cm, Low -10 C, High -6 C, Light gusting moderate W wind.Wed: Cloudy with sunny periods, Low -16 C, High -10 C, light W wind.

Snowpack Summary

Incoming new snow is building fresh storm slabs and is falling on a persistent slab made up of 3 weak interfaces in the top 30 to 50cm of the snowpack. Depth and distribution of these weak surface hoar/facet layers varies within the terrain; although buried surface hoar has consistently been found in sheltered features at TL.

Avalanche Summary

Avalanche control on Parkers Ridge Friday produced 2 large avalanches, size 2 and 2.5 on a N aspect running as the the persistent slab. On the 18th of 18 shots placed, a large crown appeared up to 1.5m thick x 150m long x 300m wide - interesting display of the variability in sensitivity and spacial distribution of buried weaknesses.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Storm Slabs

Incoming new snow and wind will build fresh storm slabs. If triggered these may step down and trigger the persistent weaknesses in the upper snowpack.

The new snow will require several days to settle and stabilize.Minimize overhead exposure during periods of heavy loading from new snow, wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

This problem is made up of 3 significant interfaces in upper snowpack. Incoming new snow may overload these layers, which have recently been reactive to skier testing and explosive control work, producing a few very significant results.

Carefully evaluate terrain features by digging and testing on adjacent, safe slopes. Avoid steep convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Loose Dry

Watch for sluffing in steep terrain.

Be cautious with gully features.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 1.5

Valid until: Jan 29th, 2018 4:00PM