Avalanche Forecast

Issued: Apr 13th, 2012 4:00PM

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

mike.koppang, Alberta Parks

Kananaskis.

A recent size 3 avalanche on Friday on Ha Ling reminds us that destructive spring time avalanches are possible. Stability will decrease throughout the day as temps warm up, especially if the sun comes out so use caution.

Summary

Confidence

Good - Freezing levels are uncertain on Saturday

Weather Forecast

An upper trough is being pushed into the forecast region by a high pressure ridge in BC and as a result, we will see some isolated flurries throughout the day on Saturday. Precipitation amounts will likely only be 5-10cm but this precip should fall as snow and not as rain.

Avalanche Summary

1 size 3 avalanche on a NE aspect on Ha Ling. Slide was 1000m long with a fracture width of 300m. Depths of the crown were variable from 1.5m to 60cm. Slide ran full path taking out mature timber. Numerous loose wet slides were observed below 2000m due to the recent rain. Two loose wet slides covered the closed section of HWY 742 below the EEOR overnight. Observations were limited in the southern part of the forecast region due to limited visibility.

Snowpack Summary

An isothermal snow pack can now be found at lower elevations. New snow that fell over the past 24hrs was rapidly settling into a soft slab due to the mild temperatures.

Problems

Storm Slabs

Thin storm slabs are developing in Alpine terrain on all aspects due to the variable winds over the past 24hrs. Additional snow fall overngiht and throughout the day on Saturday will make this problem more reactive.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

The Feb surface hoar and basal facets are still a concern in the snowpack. Solar radiation and large loads, such as cornices, triggered avalanches up to size 3.5 recently. The spring transition could see more slides stepping down to these layers.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 7

Loose Wet

Loose wet slides up to size 1.5 occurred on Friday on all aspects at lower elevations due to warm temps throughout the day. Pay close attention to terrain that is overhead as you travel. Lower elevation snowpack is isothermal in some thinner areas.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Apr 14th, 2012 9:00AM