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

Mar 12th, 2014–Mar 13th, 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 and human triggered avalanches likely.
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

South Columbia.

The current snowpack presents a serious challenge. Check out our latest blog for a look into the recent avalanche cycle and our best guess into what the future holds.

Confidence

Poor - Freezing levels are uncertain

Weather Forecast

Synopsis: A ridge of high pressure dominates the pattern for most of Thursday giving way to a pacific front Friday. Freezing levels are forecast to remain at spring like heights for the period (1300m - 2000m). Look for clearing skies Saturday. There is very little consistency from one model to the next at this time, thus my confidence in this forecast is quite poor.Thursday: Freezing Level: 1300m - 2000m; Precip: nil; Wind: Light, SW | Mod W at ridgetop.Friday: Freezing Level: 1200m - 2000m; Precip: 4/15mm - 4/20cm; Wind: Light, SW | Mod SW at ridgetop.Saturday: Freezing Level: 800m - 1900m; Precip: 0/4mm - Trace/5cm; Wind: Mod, W | Strong SW at ridgetop.

Avalanche Summary

On Monday explosive control produced storm and deep persistent slab avalanches to size 3.5 which occurred on all aspects at treeline and above. On the same day a splitboarder triggered a size 2.5 storm slab on a west aspect in the Revelstoke area. No injuries were reported. In the southeast corner of the region a vehicle remotely triggered a size 2.5 slab avalanche from the ridge above. The February 10th interface was responsible for this event.The action continued into Tuesday with skier and explosive triggered avalanches to size 3. Natural avalanches to size 2 were also observed.Last Saturday's avalanche fatality occurred in the Keefer Lake area northeast of Cherryville. The avalanche, which occurred in a cut block at about 1700m, involved 3 sledders who were in a party of 6. 2 of the men were able to inflate their airbags and were partially buried. The deceased was reportedly not able to inflate his airbag, and was buried approximately 5m below the surface.

Snowpack Summary

50 - 120 cm of recent storm snow overlies small surface hoar in sheltered areas and a sun crust on previously sun exposed slopes. In wind exposed terrain these new accumulations have been pushed into much deeper deposits by generally moderate southwest winds. The recent storm snow may be particularly reactive in high elevation lee terrain or on sun-exposed slopes where it likely overlies the buried crust. Low elevation terrain and sun-exposed features are likely seeing a daily melt-freeze cycle. At ridgetop cornices are large, unsupported and waiting for the right trigger.The mix of weak surfaces which were buried on February 10th is still reactive. This persistent interface lies between 80 and 250cm below the surface, and includes surface hoar, well developed facets and a mix of hard surfaces which remain widespread at all aspects and elevations. This deeply buried layer continues to fail with remote triggers in isolated terrain. Likely triggers include a surface avalanche in motion, a cornice fall and solar radiation.For the most part, the mid and lower snowpack are strong and well consolidated.

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.

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.