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 unlikely, human triggered possible.
Alpine
Natural and human triggered avalanches likely.
Treeline
Natural and human triggered avalanches likely.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
South Columbia.
Confidence
Poor - Due to limited field observations
Weather Forecast
Synopsis: A broad and persistent low pressure center off the BC coast and a steady southwesterly flow over the province will maintain mild temperatures and light to moderate precipitation for the next few days.Sunday: Light to locally moderate snowfall – 10-15 cm, the freezing level is around 800-1000 m, winds are moderate from the south. Monday: Light to moderate snowfall – 5-15 cm, the freezing level is around 1000 m, winds are light to moderate from the southwest. Tuesday: Moderate to locally heavy precipitation, the freezing level should jump to 1800 m.
Avalanche Summary
Recent observations include several natural or explosive triggered avalanches up to size 2 from the north part of the region. The size and likelihood of both natural and human triggered avalanches will increase with forecast snow and wind. We welcome all field observations at [email protected].
Snowpack Summary
An additional 20-30 cm of heavy new snow has fallen in the past 24 hours. This dense new snow sits on a crust and/or surface hoar layer, now down 35-50 cm. In addition, expect to find dense wind slabs in exposed lee terrain at and above treeline. Deeper in the snowpack you might find a thin, spotty surface hoar layer about 85cm down. As well, the early November rain crust now sits over 100cm down in most locations (at treeline and above) and may exist in combination with facets. These layers seem to have been unreactive in recent days, but may have the potential to 'wake-up' with additional loading producing surprisingly large and destructive avalanches.The snowpack depth in the alpine ranges from 130-225 cm, and treeline is around 150 cm.
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.