Avalanche Forecast

Issued: Jan 7th, 2014 8:27AM

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

Tim Haggarty, Parks Canada

Waterton Lakes.

Ski season seems to have finally arrived! Despite the new snow, remember to be conservative with terrain choice. A dry and windy December has left us with a thin snowpack that can vary a great deal in a short space.

Summary

Weather Forecast

Temperatures look to be fairly steady with freezing levels right around the townsite level. We expect the West winds to continue. 10 to 20 cm of snow is expected through to the weekend arriving mainly Thursday and Friday. This additional snow combined with the wind will likely cause and increase in the avalanche hazard as we approach the weekend.

Snowpack Summary

40 cm fell with the Storm Friday. Strong West winds blew Sunday and Moderate West winds continued to build fresh wind slabs Monday. Thin spotty slabs can be found behind exposed features well below treeline and more significant slabs exist at higher elevations. 30 to 40 cm off of the ground a weak layer of sugary faceted crystals remains a concern.

Avalanche Summary

Observations on a wildlife survey flight Sunday confirmed a widespread cycle of loose dry avalanches to sz 2 throughout the Park. In N and E alpine slopes that were rapidly loaded during the storm these minor slides triggered several examples of deep persistent slabs to sz 2.5 and up to 1.5m deep on steep, planar or unsupported slopes.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Wind Slabs

Strong West winds made quick work of the 40 cm of snow that fell before the weekend. Thin, spotty wind slabs found behind exposed features well below treeline can be easily triggered by skiers. Expect these slabs to be more significant TL and above.

Be cautious as you transition into wind affected terrain.The best powder will be found in sheltered locations at or below treeline.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Deep Persistent Slabs

This weak layer of snow persists 30 to 40 cm above the ground. Triggering a wind slab could produce the large load necessary to wake this layer up. Use caution in thin areas particularly with steep, planar, or unsupported slopes.

Use conservative route selection, stick to moderate angled terrain with low consequence.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Jan 10th, 2014 4:00PM