Avalanche Forecast

Issued: Apr 15th, 2014 8:38AM

The alpine rating is low, 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

Wednesday: Cloudy with flurries and isolated sunny breaks. The freezing level is around 1600 m and ridge winds are light to moderate from the SW. Thursday: Cloudy with flurries or showers – 5-15 cm. The freezing level is around 1800 m. Winds are moderate from the South. Friday: Cloudy with flurries or showers. The freezing level is around 1800 m. Winds are light to moderate from the W-SW.

Avalanche Summary

No new avalanche activity was reported on Monday. Observers did report evidence of several recent natural cornice collapses, some of which triggered thin slabs in steep terrain.

Snowpack Summary

Warm temperatures and strong sunshine likely created a solid melt-freeze crust on the surface in most places. High shady slopes may still have 10-15 cm of dry snow sitting on a previous crust. The surface crust will likely break down during the day resulting in moist or wet surface snow. 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

Possible

Expected Size

1 - 4

Deep Persistent Slabs

This problem is becoming less likely with more cloud and slightly cooler temperatures but it still deserves some respect. Minimize your exposure on large steep alpine slopes, especially if the snow surface is moist or wet.

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 16th, 2014 2:00PM