Avalanche Forecast

Archived

Apr 5th, 2014–Apr 6th, 2014

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Kootenay Boundary.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Overnight and Sunday: Freezing levels dropping overnight to about 1500 metres combined with moderate Southwest winds and light precipitation. Freezing levels rising up to 2300 metres with moderate Westerly winds during the day. Expect broken skies with sunny periods.Monday: Freezing levels are expected to continue to rise through the night and reach about 2600 metres during the day. Broken skies may result in periods of strong solar radiation to add more warmth to the snowpack.Tuesday: Southwest winds increasing to strong with cloudy skies and moderate to heavy precipitation beginning in the afternoon. Freezing levels remaining at 2600 metres overnight and then lowering slightly during the day.

Avalanche Summary

No new avalanches reported.

Snowpack Summary

Another 5-10 cm of new snow overnight has increased the recent storm slab to 10-30 cm in depth. The new thin storm slab is sitting on a 2-5 cm melt-freeze crust that developed over the past few days on all but shaded North aspects in the alpine. This crust has been reported to be "knife" resistance in some parts of the region and may have a layer of surface hoar below the new storm snow. There is now about 75 cm of well compacted snow above the March 10th melt-freeze crust. In some areas the March 10th crust is helping to bridge over the deeply buried late January/early February persistent weak layer. The Jan/Feb deep persistent weak layer continues to be a concern for very large destructive avalanches. Releases on this layer may be more likely during periods of strong solar radiation and/or prolonged warm temperatures at alpine elevations.

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.

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.