Avalanche Forecast

Issued: Jan 29th, 2018 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

A good day to stay away from avalanche terrain. Some natural avalanches are reaching the end of their run-outs, and activity is expected to increase tomorrow with the incoming storm.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

A burst of wind and snow is expected overnight Monday, bringing 15 to 20cm of new snow by Tuesday morning. Winds will be strong to extreme out of the west, creating perfect conditions for further wind slab development. Tuesday is looking like a cloudy with sunny periods and isolated flurries. Strong winds will continue with alpine temperatures near -10 °C.

Avalanche Summary

A size 2.5 or 3 (extent of debris unconfirmed) occurred sometime today on Tent Ridge, on an East aspect at 2450m. This initiated down about 100cm and then stepped even deeper part way down the avalanche path. In addition a size 2.0 occurred on Little Tent Ridge on a SE aspect at 2350m. This one wasn't quite as deep but it did propagate across the entire feature. A couple of size 2.0 to 2.5 slab avalanches occurred on the Goat Range in the past 24hrs, initiating in the upper Alpine and running to 1/2 or 3/4 path.

Snowpack Summary

Strong to extreme West winds have created fresh wind slabs in all Alpine and Treeline terrain in lee and cross-loaded terrain. At Treeline and below several buried weak layers exist. These are surface hoar layers buried 30, 50 and 80cm on average. All these weak layers are producing sudden planar shears with the Dec 15th layer down 80cm being perhaps the most concerning. Recent avalanche activity has been observed to step down to this Dec 15th layer creating large avalanches.

Problems

Wind Slabs

A bunch of snow is expected overnight with very strong westerly winds. Wind slabs will be very touchy to human triggering.

Minimize overhead exposure during periods of heavy loading from new snow, wind.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Avoid steep lee and cross-loaded slopes

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1.5 - 3

Persistent Slabs

We may be near the tipping point for avalanche activity to begin on any one of several buried weak layers. Large avalanches are occurring on these layers.

Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.Avoid convex rolls at and below treeline where buried surface hoar may be preserved.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1.5 - 3

Valid until: Jan 30th, 2018 2:00PM