Avalanche Forecast

Issued: Mar 13th, 2016 4:40PM

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

Ruari Macfarlane, Parks Canada

Waterton Lakes.

Winter temperatures, winter snow, and winter avalanche problems! It's all back... bring your smile, your skis / snowshoes, your avalanche rescue equipment, and your savvy.

Summary

Weather Forecast

A little more snowfall for Sunday night, with cooling temperatures - models disagree as to just how much, but upto 10cm. Monday-Wednesday, expect winter-like temperatures, and unsettled weather: a mix of sun & cloud, with the odd flurry. Strong Westerly winds on Monday gradually ease to Light Westerlies by Wednesday.

Snowpack Summary

25-40cm of snow has fallen since Thursday, accompanied by strong SW winds and warm temperatures . This has created dense Storm Slabs on lee slopes, bonding poorly to a crust below. A deeper crust down 60-100cm has produced alarming results in some snowpack tests at Treeline, although slope tests did not produce avalanches on this layer.

Avalanche Summary

On Saturday and Sunday, several small Storm Slab avalanches were observed in lee terrain. These started in steep terrain, or under headwalls. Two very large avalanches were observed recently near the divide. These began in steep, unsupported terrain. The dates of these are unknown, but warm storms on March 6 or March 10 were likely responsible.

Confidence

Forecast snowfall amounts are uncertain on Sunday

Problems

Storm Slabs

New snowfall and wind loading has created thick storm slabs on many lee slopes. These have been bonding poorly to crusts below. They will slowly become less sensitive to triggering with the cold temperatures forecast.

Avoid lee slopes with any steepness over 40 degrees.Use caution in lee areas. Recent snowfall mixed with wind loading has created storm slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Cornices have been growing lately. They may become touchy for a day or two, as they adjust to colder temperatures.

Avoid steep slopes below cornices.Stay well to the windward side of corniced ridges.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Mar 16th, 2016 4:00PM