Avalanche Forecast

Issued: Dec 29th, 2017 8:01AM

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

andrew jones, Parks Canada

Glacier.

With the addition of last night's new snow, careful evaluation of the December 15 surface hoar layer should be a part of your decision making process.

Summary

Weather Forecast

Cloudy with sunny periods as last night's storm exits the province. A slight alpine temperature inversion is in place, although temps will remain cold with an alpine high of -13. Ridge winds will be light from the east. The next round of precipitation arrives this evening with 8cm forecast for tonight with cold temps and periods of strong winds.

Snowpack Summary

20cm of new snow fell overnight with relatively light winds and cold temperatures. An isolated surface hoar/ facet layer (December 27) is buried 20cm. The Dec 15 surface hoar layer, which is widespread at treeline, is buried 60cm. Cold temperatures have hindered slab development in the upper snowpack.

Avalanche Summary

No new avalanches were observed yesterday.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Loose Dry

With 20cm of new cold dry powder, natural and human triggered avalanches are expected in steep terrain. It is possible for small loose avalanches to trigger deeper instabilities, especially near ridge lines or where Dec 15 surface hoar is preserved.

Avoid travelling on ledges and cliffs where sluffing may have severe consequences.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

The December 15 surface hoar layer is widespread around treeline and buried 60cm. Cold temps have kept the slab from gaining cohesion, but it may be reactive on steep unsupported and/or wind affected terrain.

Watch for signs of slab formation, such as whumpfing and shooting cracks.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Dec 30th, 2017 8:00AM