Avalanche Forecast

Issued: Apr 16th, 2014 8:50AM

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

Peter, Avalanche Canada

South Rockies.

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 - Due to the number of field observations

Weather Forecast

Tonight and Thursday: Cloudy with showers or flurries â€“ trace tonight, 5 cm/mm Thursday. The freezing level is around 2200 m. Winds are moderate from the South.Â Friday: Cloudy with flurries or showers and isolated sunny breaks. The freezing level is around 1800 m. Winds are moderate and gusty from the W-NW.Â Saturday: Cloudy with sunny periods and a chance of showers. The freezing level rises to 2300 m and ridge winds are light to moderate from the south.

Avalanche Summary

No new avalanche activity was reported on Monday or Tuesday. Most of the recent reported activity has been limited to loose wet slides and cornice collapses from warming and solar radiation.

Snowpack Summary

Up to 5 cm of new snow sits on a solid and thick melt-freeze crust above 1500 m. High high north aspects may have 15-30 cm of dry snow sitting on a previous crust, and possibly more where wind loaded. Warm temperatures and periods of sun will likely create moist or wet surface snow and may soften the underlying crust. The mid and upper snowpack consists of a mix of moist snow and well bonded crusts. 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 that will see the intense sun tomorrow. 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

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

Unlikely - Possible

Expected Size

1 - 4

Deep Persistent Slabs

The likelihood of triggering this problem is low, but the consequences of triggering would be very high. Use extra caution if it is raining or the sun is strong.

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

Expected Size

3 - 6

Valid until: Apr 17th, 2014 2:00PM