Avalanche Forecast

Issued: Feb 1st, 2019 3:01PM

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

matt.mueller, Alberta Parks

Kananaskis.

20-30cm of snow is on its way. While not a huge amount, we are expecting a brief natural cycle tomorrow.

Summary

Confidence

High -

Weather Forecast

All forecasts are saying snow is on the way. Amounts vary, but 30cm seems to a common number for the Spray area. Unfortunately moderate to strong southwest winds will accompany the snow. As for temperatures, they will remain warm until later in the week end. Tomorrow's high is -5C. Today saw above zero temps on the road.

Avalanche Summary

Nothing noted today due to poor visibility.

Snowpack Summary

The leading edge of the approaching storm has so far given us only 4cm near the divide. It is exactly what the forecast said would happen (don't hear that much!). That's giving us confidence in there being a further 20cm by tomorrow. The forecasted winds are also correct. As of this afternoon ridgetop winds were around 50km/hr from the SW. Windslabs are building on any easterly aspect in the alpine and treeline areas. How well these slabs stick to the underlying windslabs is the question. Given how long the slabs were exposed for, it may be a poor bond at first. Treeline saw little change today, but again, if there are new slabs by tomorrow expect them to be poorly bonded due to surface facetting. In general, this 20cm would be considered a rapid load. The Jan 17th surface hoar is isolated, but where it exists, expect it to be down 30cm and possibly reactive. Deeper layers will be stressed trying to support the weight of a 20-30cm storm.

Problems

Wind Slabs

The fresh windslabs will be most concerning tomorrow. Expect a poor bond in the alpine due to the hard slab.

Caution in lee and cross-loaded terrain near ridge crests.New snow will require several days to settle and stabilize.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Deep Persistent Slabs

Be aware that this new snow load will stress the deeper layers. There is a bridging effect with the firmer alpine snowpack, but the treeline snow has less density, meaning it will be more stressed while it adjusts.

Carefully evaluate and use caution around thin snowpack areas.Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Loose Dry

There is a chance of loose dry avalanches being a problem. Gullies in the alpine and steep treeline features are where it could pose a risk.

Choose ice climbs that are not exposed to avalanches from above.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Feb 2nd, 2019 2:00PM