Avalanche Forecast

Issued: Feb 15th, 2016 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Touchy wind slab conditions exist. Conservative route selection is advised.

Summary

Confidence

High

Weather Forecast

Tuesday will be cloudy with sunny periods and isolated flurries. Only minimal snowfall accumulations are expected. Temperatures should reach a high of -5 °C in the Alpine with ridge-top winds out of the west at 35 km/h gusting to 90 km/h. Wednesday and Thursday could see snowfalls in the 20cm range with strong SW winds.

Avalanche Summary

A moderate sized avalanche cycle is on-going related to the recent persistent strong Northerly winds. Natural avalanche activity up to size 3.0 (average size 2.0 to 2.5) occurred today in specific Alpine terrain. Most slab avalanches occurred immediately below ridge crests under cornice features, or were triggered by loose dry avalanches from very steep alpine terrain. Fracture lines ranged from 50 to 100cm deep. The activity occurred on NE, E, S and SE aspects at elevations of 2400m and above. In addition, solar triggered slides up to size 1.5 occurred in the afternoon on steep S, SW and W aspects.

Snowpack Summary

An additional 12cm of new snow overnight brings recent storm snow totals to 20 to 30cm at Treeline. Alpine and upper Treeline areas continue to see wind slab development on NE, E, SE, and S aspects due to persistent winds that have been out of the North for the past 2 days. An avalanche cycle due to wind loading is on-going (see avalanche discussion). Moist snow was observed on steep solar aspects in the afternoon. Cornices have grown significantly over the past 48 hours. Test profile at 2350m today shows easy shears at the storm snow interface, moderate shears down 40cm at an old wind slab interface and hard shears down 115cm on a layer of facets. The Jan 6th interface buried 80cm did not produce a shear in our tests today.

Problems

Wind Slabs

Persistent winds have created touchy wind slab conditions in the Alpine and just down into Treeline. In addition to typical lee and cross-loaded features, be aware of reverse wind loading onto buried sun crusts on SW, S and SE aspects.

Avoid lee and cross-loaded terrain near ridge crests.>Avoid freshly wind loaded features.>Be aware of the potential for wide propagations.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Persistent Slabs

Avalanches initiated in the upper snowpack could step down to the Jan 6th interface and produce very large avalanches. Thin snowpack areas are common trigger points.

Choose well supported terrain without convexities.>Extra caution needed around cornices with current conditions.>Avoid areas with overhead hazard.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 5

Loose Wet

Solar radiation is intense when the sun is shining. Be aware of overhead terrain and plan your trip to avoid solar aspects in the afternoon.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 16th, 2016 2:00PM