Avalanche Forecast

Issued: Feb 10th, 2014 4:27PM

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

tim haggarty, Parks Canada

Waterton Lakes.

With incoming weather and weak surface snow, a rapid progression to higher hazard could occur over the next few days. Watch snowfall amounts carefully.

Summary

Weather Forecast

Active weather crossed the divide early Monday with a warm front bringing light precip, moderate SW winds and a significant warming trend. About 15cm is expected by midday Tuesday. A second system Wednesday looks very similar with perhaps stronger winds. Expect new snow, warm temps, and strong winds to rapidly form slabs over the described snowpack

Snowpack Summary

20 to 30 cm of weak, faceted snow is bonding poorly to a variety of surfaces: suncrust SW to SE and previous wind effect open areas. Faceting also continues in the bottom 40 cm of the snowpack where depth hoar has now replaced old crusts, the slab of hard snow above this provides all of the strength to our snow pack but this is extremely variable.

Avalanche Summary

Widespread minor wind generated surface sluffing in steep terrain has gouged into some wind affected slopes to release very soft slabs that wind loading has created over the weak surface facets. Skiers in steep terrain will find very easy sluffing 20 to 30 cm deep. All of these events run far on the firm surfaces until they hit lower angle terrain.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Storm Slabs

As new snow falls and is redistributed by W winds, expect slabs to form quickly or to contribute to soft windslabs that already exist at Treeline and above. In recent days even very soft slabs have failed easily over weak, faceted surface layers.

Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Loose Dry

In terrain over 40 degrees skiers may easily sluff the Surface Snow which will continue to gouge out a trough until it hits lower angled terrain. These events occur naturally in very steep terrain. Expect this to get worse with more snow.

Be very cautious with gully features.Good group management is essential to manage current conditions safely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Deep Persistent Slabs

This weak snow under the entire snowpack remains a concern especially in thin areas. As warming and loading occurs, avalanches described in the problems above could provide a large load triggering larger events on this layer.

Avoid shallow snowpack areas where triggering is more likely.Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.

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

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Feb 13th, 2014 4:00PM