Avalanche Forecast

Archived

Apr 11th, 2015–Apr 12th, 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.

Spring Avalanche Danger is variable and can range from Low to High. Travel early in the day is recommended as conditions can change rapidly due to daytime warming. Pay attention to the integrity of crusts formed overnight and rising temps. Synopsis

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Sunday

Weather Forecast

Sunday will be a mix of sun and cloud with a chance of some convective flurries throughout the day. Alpine temperatures will be around -9C and winds will be moderate out of the west. Freezing levels should be around 1900m. When the sun does come out, stability will decrease quickly so pay close attention the the aspect you are travelling on or underneath on your way home.

Avalanche Summary

A few loose dry avalanches were observed from steeper terrain on Saturday. Also there was a report of a sz 2.5 on a N aspect near the "Sharks tooth" peak in the commonwealth area. This avalanche was likely triggered by a cornice collapse.

Snowpack Summary

Over the past 24hrs up to 15cm of new snow has fallen with moderate NW winds. This new snow will form thin new storm slabs and bury the previous windslabs that we were talking about. Cornices are also large and there have been reported failures of late with the large loads triggering slabs on the underlying slopes. The basal facets have not been active in some time but as temperatures warm up, we may start to see them become more active. Temperature, Aspect and time of day are all relevant at this time. The quality of the freeze overngiht will play a large role in regards to stability. When the snowpack is in its frozen state, the avalanche danger is relatively low-moderate. As it begins to melt, it will become less stable and eventually, the danger may increase to high. Solar aspects will see the biggest changes, especially in steeper, thin, rocky terrain. Northern aspects still have dry powder snow and a generally winter snowpack. Evaluate the terrain and overhead hazard as you travel. To review common spring avalanche problems go here

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

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.