Avalanche Forecast

Issued: Apr 17th, 2014 9:00AM

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

Avalanche Canada Peter, Avalanche Canada

This bulletin was created using very limited field data. If you are out in the mountains, please send your observations to forecaster@avalanche.ca

Summary

Confidence

Poor - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Friday: Cloudy with sunny breaks and scattered showers or flurries (~5-10 cm). The freezing level is around 1800 m. Winds are moderate gusting to strong from the west. Saturday: A mix of sun and cloud and warm! The freezing level rises to 2600 m and ridge winds are moderate to strong from the southwest. Sunday: Cloudy with sunny breaks and a chance of showers. The freezing level rises to 2200-2400 m and ridge winds are moderate from the west.

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

Above around 1800 m the mid and upper snowpack consists of layers of moist snow mixed in with several well bonded crusts, and around 10-15 cm of new snow on top. High north aspects may have around 30 cm of settled storm snow sitting on a crust, possibly more where wind loaded. Warm temperatures and periods of rain have made the snow surface wet below 1800 m, and at low elevations the entire snowpack is probably moist or wet. 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

Cornices

An icon showing Cornices
Daytime heating makes cornices droop and become unstable. A large cornice release could also trigger a deep persistent weak layer and produce a very large avalanche.
Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 4

Wind Slabs

An icon showing Wind Slabs
If we get a little more snow than forecast we could see fresh wind slabs form in exposed lee terrain. Where the new snow is wet it may release as loose wet slides in sufficiently steep terrain.
Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 18th, 2014 2:00PM

Login