Avalanche Forecast

Issued: Apr 18th, 2014 8:16AM

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

Peter, Avalanche Canada

South Rockies.

Check out this video by the CAC South Rockies field team describing current conditions and what to expect in the South Rockies and Lizard Range over the next couple of weeks. Please send us your observations at forecaster@avalanche.ca

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Saturday: A mix of sun and cloud. The freezing level rises to around 2000-2200 m and ridge winds are moderate to strong from the S-SW. Sunday: Sunny with cloudy periods and possible flurries. The freezing level is around 1800-2000 m and ridge winds are moderate from the west.Monday: Cloudy with sunny breaks. The freezing level jumps up to around 2500 m. Wind are moderate from the S-SW.

Avalanche Summary

On Thursday, the CAC field team observed a natural cornice failure which triggered a thin slab below near Window Mountain in the Crowsnest Pass. There were also several loose wet avalanches from steep terrain. The team also saw the remnants of a natural deep persistent slab that broke several large mature trees. This avalanche probably occurred in the past week or so, and most likely during a warming event.

Snowpack Summary

Recent snowfall amounts probably vary throughout the region but I would expect there is around 15-30 cm in most places. The snow line has probably hovered between 1500 and 1700 m. The new snow is sitting on hard crust and may not bond well initially. Higher north aspects may have as much as 50 cm of settling dry powder. It looks like we should see cool temperatures overnight which will likely form a new surface crust at lower elevations. The deep facet/crust persistent weakness buried at the beginning of February (now down up to 80-100+ cm) should stay on your radar, especially on all alpine slopes during sunny periods. Any activity at this interface would be large and destructive. Also, give large sagging cornices a wide berth when traveling on or below corniced ridges.

Problems

Wind Slabs

New wind slabs may have formed in exposed lee slopes and cross-loaded features.

Avoid freshly wind loaded features.>Highmark or enter your line well below ridge crests to avoid wind loaded pillows.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Wet

Expect loose wet slides on steep sun exposed slopes during the day. Also, give cornices a wide berth when traveling on or below ridges.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

The potential for deep persistent slabs will increase when the sun is shining and temperatures are warm. Minimize exposure to big alpine slopes when things are heating up.

Be aware of the potential for large, deep avalanches due to the presence of buried persistent weak layers.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Apr 19th, 2014 2:00PM