Avalanche Forecast

Archived

Apr 3rd, 2014–Apr 4th, 2014

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

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 unlikely, human triggered possible.

Regions

Kootenay Boundary.

Confidence

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

Weather Forecast

Overnight and Friday: Light snow starting overnight and continuing through the day. Expect 3-5 cm by morning and another 3-5 cm during the day. Moderate to strong Southwest winds should develop overnight. The freezing level should drop down to 1300 metres overnight and then rise up to about 1800 metres.Saturday: Freezing level dropping to 1300 metres overnight. Flurries or convective snow showers combined with moderate Southwest winds and freezing levels rising to 1800 metres. Moderate snow fall beginning in the evening.Sunday: Expect 5-10 cm by morning combined with moderate Southwest winds. Freezing levels rising to 2000 metres.

Avalanche Summary

No new avalanches reported.

Snowpack Summary

Forecast new snow and Southwest wind may result in a new storm slab. High freezing levels may limit crust recovery before the new snow arrives. There are a few crusts in the snowpack that we are following. The March 25th crust is now down about 20-30 cm buried below a well settled layer of recent snow. The March 10th crust is buried down 60-90 cm and is reported to be widespread across the region up to about 2000 metres elevation. The facet/crust persistent weakness buried at the beginning of February is now down 70 - 200cm, and has been highly variable in terms of reactivity. In areas where the strong and supportive crust exists, triggering this layer has become unlikely. Avalanches releasing on this deeply buried weak layer could be very large and destructive.

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.