Avalanche Forecast

Archived

Apr 12th, 2015–Apr 13th, 2015

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Kananaskis.

Up to 30cm of recent snow has fallen with moderate winds. Watch for new windslabs building. Danger rating are no longer being issued to rapidly changing spring conditions. For an explanation of the current spring situation click here

Confidence

Good

Weather Forecast

Monday is looking to be a cloudy day with isolated sunny periods. We may see a few cm of new snow but not a significant amount as the storm is winding down. Temps in the alpine will be in the -5 range with winds again moderate out of the SW. Freezing levels will be around 2100m.

Avalanche Summary

No new avalanche activity was observed on Sunday but observations were limited due to visibility.

Snowpack Summary

Up to 30cm of recent storm snow has fallen. Winds have increased into the moderate range out of the SW and as a result we are seeing new wind slabs develop in open wind affected terrain. Field tests were showing these slabs to be about 30cm thick and despite them not being reactive in areas that we traveled on Sunday we believe that in more open areas along ridgelines and in gullied terrain, there is a potential for human triggering. The sun didn't shine on Sunday at all, in fact it was a rather wintery day, but if the sun does come out its important to remember that stability will decrease quickly. Avalanche danger at this time of year is highly variable based upon aspect, temperatures, solar radiation input as well as time of day. Cornices are also growing with the input of new snow and moderate winds. New load and warm temps can cause these cornices to fail so limit exposure time around this type of problem. Keep an eye on these factors as you travel throughout the mountains. To review common spring avalanche problems click here. This is the scenario that we are in at this time.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.