Avalanche Forecast

Issued: Mar 2nd, 2016 3:00PM

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

matt.mueller, Alberta Parks

Kananaskis.

The persistent layers that plagued the northern regions is becoming more of a concern here recently. Forecasters triggered a large avalanche involving the Jan 6th today. Avoid thin snowpack areas in big terrain right now.

Summary

Confidence

High

Weather Forecast

The winds will be a very important component over the next 48hrs. Tonight they are expected to pick up and hit 55km/hr at 2500m. Tomorrow they will be steady at 50km/hr with gusts up to 90. They will be steady out of the west for the next while. Isolated flurries will bring only a few cm's close to the divide. The alpine high will be -4 tomorrow. The freezing level will creep up to 1800m.

Avalanche Summary

Forecasters had a near miss today and kicked off a sz2.5. It was on a moraine feature (Murray Moraines area) that drops into more shallow terrain. The avalanche propagated almost 100m and was up to 80cm deep. The Jan 6th was the failure plane and the start elevation was 2300m. Aside from that, there were also some small loosed dry avalanches noted as well as cracking and whumphing(within the storm snow) in shallow areas(Aster Lake region).

Snowpack Summary

Last night saw 5-10cm's of new snow throughout the region. Close to the divide seemed to get the most with 11cm. The winds that accompanied the snow were slightly less than expected, but still enough to create fresh windslabs at upper treeline and alpine. Including this snow, there is now 15-20cm of recent snow on top of the Feb 27th interface. The Feb 27th interface consists of a crust on south aspects, and a density change on polar aspects and the alpine. The bond with this layer is questionable, and in areas with a stiffer slab may be suspect. The Feb 11th layer is similar in many ways, variable with a suspect bond and aspect/elevation dependant. It is down 40cm's. The Jan 6th layer appears to be waking up in places. Especially in thin areas at treeline and alpine elevations. It is down 60-90cm's at treeline/upper treeline and is becoming more reactive with the additional load.

Problems

Storm Slabs

Lots of snow available for transport right now. Lee and crossloaded areas near ridge crests will likely have this problem. If the winds pick up this problem will extend into low elevation terrain.

Avoid freshly wind loaded features.>Avoid lee and cross-loaded terrain near ridge crests.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Where the Feb 11th is a crust, we can expect a more pronounced problem. On non-solar aspects expect a more stubborn slab, but it is suggested to dig and do some research on how touchy it is.

Dig down to find and test weak layers before committing to a line.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

These are waking up. We are finding thin areas to more and more suspect as the load increases. Big terrain should be treated with extreme caution while the internal snowpack adjustment takes place. Large triggers are also concerning.

Be aware of thin areas that may propogate to deeper instabilites.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 5

Valid until: Mar 3rd, 2016 2:00PM