Avalanche Forecast

Issued: Jan 31st, 2017 4:36PM

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

Ruari Macfarlane, Parks Canada

Waterton Lakes.

Although forecasts predict only a few CM of snowfall, it's falling as this is written. If new snowfall amounts approach 10 cm, take a cautious approach to steep terrain in the Front Ranges (Ice climbers, this could mean you).

Summary

Weather Forecast

The arctic front marches South into the USA on Tuesday evening, causing light upslope snowfall. Temperatures fall to a steady -17 at Treeline, with flurries and Moderate NE winds, through Thursday. Only a couple of CM are expected. On Friday, skies clear and temperatures rise, as increasing SW winds boot the upslope back to where it belongs....

Snowpack Summary

Extreme SW winds on Sunday caused widespread scouring, with thin pockets of stubborn Wind Slab found on sheltered Treeline slopes on Tuesday. Solar aspects below 2000m are breakable crust, while sheltered aspects still hold some soft snow. The upper snowpack is supportive, over a faceted but strengthening lower snowpack.

Avalanche Summary

No new avalanches have been reported or observed. At Treeline on Tuesday, localised cracking from ski tips was observed in a Pencil hard, 5-10cm surface Wind Slab.

Confidence

Forecast snowfall amounts are uncertain on Wednesday

Problems

Wind Slabs

Thin pockets of Wind Slab are expected to be hard and unreactive in wind exposed areas, but may be soft enough to trigger in typically sheltered areas. The problem may switch to S and W aspects if we get more snowfall than forecast with NE winds.

Keep an eye out for reverse loading created by an upslope storm.Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 1

Deep Persistent Slabs

Although it has been several weeks since natural activity was last seen on the deeply buried December Facets / November Crust, the consequences of triggering a large avalanche from just the wrong shallow, faceted spot, could be dire.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Feb 3rd, 2017 4:00PM