Avalanche Forecast

Issued: Jan 30th, 2019 4:00PM

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

Timothy Johnson, Parks Canada

Jasper.

There is large uncertainty around forecast snowfall amounts on Friday and Saturday.

Summary

Weather Forecast

Thursday will be cloudy with scattered flurried. Treeline high temperature of -6C, with light-Moderate SW winds. Friday-Saturday: Temperatures stay steady around -5 until plummeting Saturday afternoon. 30cm of snow is forecast with light to moderate winds from the SW A detailed mountain weather forecast is available from Avalanche Canada.

Snowpack Summary

Sunday's snowfall along with SW - NW winds created wind slabs in lee and cross-loaded terrain. Expect a crust on solar slopes at treeline. The upper snow pack continues to settle and the layer of weak surface hoar is now buried 5-10cm deep. Below, a strong mid-pack sits over depth-hoar in the lower third of the snowpack giving sudden results.

Avalanche Summary

A natural Size 3 Deep Persistent slab was observed Monday on a steep (35+ degrees) Alpine South-West facing slope. Triggered by a smaller windslab, it stepped down to depth hoar and the ground. Several windslabs to Size 2 were also observed (Alpine S and E aspects). Help forecast - share observations HERE, on the Mountain Information Network!

Confidence

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

Problems

Wind Slabs

New snow on Sunday arrived with Strong winds (ranging from SW to N) creating windslabs over a variety of surfaces, including suncrust, surface hoar, and wind pressed areas.

Use caution in lee and cross-loaded areas. Recent wind loading has created new wind slabs.Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

A natural avalanche Monday on this layer shows that only minor changes may wake this generally dormant dragon. Triggering is most likely in thin areas, with variable snowpack depth. Use terrain choice and safe practices to minimize consequences.

Avoid thin, rocky or unsupported slopes.Ride slopes one at a time and spot for your partners from safe locations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3.5

Valid until: Jan 31st, 2019 4:00PM