Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Apr 19th, 2014–Apr 20th, 2014

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches possible, human triggered probable.

Regions

Little Yoho.

Hazard is subject to rapid change based on the duration and intensity of the sun over the day. Start early, get up high for the best skiing and get back early. DK

Weather Forecast

Expect a mixed bag of light convective snow, sun and gusty west winds. Alpine temps are expected to remain cool and freezing level to 1800ms. A good overnight freeze should make travel easy in early morning but expect any solar aspects to soften up quickly if the sun gets to them.

Snowpack Summary

HST settling and a surface crust will exist in the am and break down over the day on all aspects up to to 1800ms, higher on S and W aspects. Cornices seem to be more sensitive to the temperature fluctuations especially on the solar aspects and have been seen to trigger slabs below both in the storm snow and the deeper persistent layers.

Avalanche Summary

Control work on Sat on a solar aspect produced storm slabs up to sz 2 in the alp and a loose wet, aggressive size 2 below treeline. Natural cornice release in the alpine triggered the slope below to sz 2 and it appears they have become far more sensitive. Forecasters remain cautious about the deep basal layer being triggered from shallow areas.

Confidence

Problems

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.