Avalanche Forecast

Issued: Dec 9th, 2013 4:00PM

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

Edwin Knox, Parks Canada

Waterton Lakes.

Little Prairie 67cm, Forum Ridge ascent still only 70 to 80 with 120cm at 2150 meters on the east lee aspect. Alders, stumps and rocks continue to be a big hazard ...don't get carried away yet! It is still early December.

Summary

Weather Forecast

The Dec 2nd storm snow which came in from the NE is now being redistributed with a very strong westerly flow. These winds will blow strong from the west through the forecast period and slabs will build on easterly lee terrain. Temperatures will warm to minus single digits for treeline terrain by Thursday. Only trace amounts of new snow are likely.

Snowpack Summary

Strong westerly flow stripping windward and creating slabs on the lee. SSL at 1850 to 2150 meters BTL. Expect stiffer slabs in alpine areas that could be triggered. Tests on an E asp at 2140m on Forum Ridge showed failure down 35cm (CTH22) and deeper in the pack another weak layer down 80cm (CTH29) though it is bridged with 20cm pencil layer.

Avalanche Summary

Debris from one size 2 avalanche observed Monday falling to mid slope from very steep NE terrain on Buchanan Peak with load from strong westerly winds.

Confidence

Problems

Wind Slabs

It would be possible to trigger an avalanche in open, unanchored lee terrain. Slabs will continue to develop through the week.

Be careful with wind loaded pockets while approaching and climbing ice routes.Be cautious as you transition into wind affected terrain.

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 12th, 2013 4:00PM