Avalanche Forecast

Issued: Dec 30th, 2017 8:10AM

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

ian gale, 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

After last nights underwhelming storm we'll see another few cms out of the system as it leaves the province. Today will be mostly cloudy with some sunny periods but will remain cold with freezing level firmly at valley bottom. Winds will ease and become light westerly. An Arctic ridge will rebuild Sunday and bring back the sunny weather.

Snowpack Summary

25cm of low density new snow fell in the last 36 hrs while temps remained quite cold. An isolated surface hoar/ facet layer (December 27) is buried down 20cm. The Dec 15 surface hoar/sun crust layer, which is widespread at treeline, is buried down 60cms. Cold temperatures have hindered slab development in the upper snowpack.

Avalanche Summary

We experienced a widespread natural avalanche cycle yesterday. Numerous loose dry and storm slab avalanches ran to sz 2.5, mostly from steep terrain. Expect this cycle to continue today with avalanches having the potential to reach out into runout zones. Be aware of naturals from above especially in areas like Connaught Creek

Confidence

Wind effect is extremely variable

Problems

Storm Slabs

The 30cms of recent storm snow will remain touchy for loose avalanches in steep terrain. With all the available fetch, strong Northerly winds will have created soft slabs on lee slopes. Avalanches will have the potential to reach runouts today.

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.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Dec 31st, 2017 8:00AM