Avalanche Forecast

Issued: Feb 2nd, 2019 3:51PM

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

Alberta Parks matt.mueller, Alberta Parks

Lots of snow out there that needs some time to settle. Great skiing in sheltered trees at the moment.

Summary

Confidence

High -

Weather Forecast

The snow will taper as the cold air moves in. Only a few more cm's expected. The cold will creep in overnight tonight with morning lows of -32. Winds will swing to the south and become light. It will probably be cloudy tomorrow, but with temps like that, don't be surprised if it clears.

Avalanche Summary

At Tryste Lake today we were able to trigger a sz2 by dropping a very small cornice chunk on the slope. It pulled out the storm snow and ran to the lake. On the commonwealth side, there was a natural sz2 storm slab at treeline on a north aspect. If I was a betting man, I'd bet the farm on there being a medium size natural cycle today throughout the area that went unnoticed because of the poor visibility.

Snowpack Summary

35-45cm of new snow has fallen in the last 24hrs. With the warm temps during the storm the snow was quick to settle and in many areas formed a soft slab almost immediately. Today we had reactive soft slabs from 2200m up. The winds also played a role in open areas at all elevations. Touchy windslabs are present at treeline and alpine on easterly aspects. What these slabs rest on is important. On north aspects the old slabs were dense with some surface facetting. On south aspects the Jan 28 sun crust is down 40cm. Both of these older layers are a poor bonding surface for the new snow. To add another variable, the Jan 17 surface hoar layer is also present. It's been hard to nail down the details of this layer, but keep an eye out for it below 2200m sheltered areas. The deeper layers are also adjusting to the new load. While not reactive today, don't forget about them and remember that they are gradually getting used to the new snow load.

Problems

Wind Slabs

An icon showing Wind Slabs
We have a variety of technically different slabs right now, but the bottom line is we have a widespread slab problem. As it cools expect them to stiffen slightly and propagate easier and further.
New snow will require several days to settle and stabilize.Caution in lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely - Certain

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Be aware that this new snow load has stressed the deeper layers. Thin areas, large triggers (cornices) could easily get this layer sliding.
Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.Carefully evaluate and use caution around thin snowpack areas.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Valid until: Feb 3rd, 2019 2:00PM