Natural avalanches possible, human triggered probable.
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 unlikely.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
Regions
South Coast.
Storm slabs up to 55 cm in depth may remain problematic Monday. Choose wind sheltered terrain features while minimizing exposure to both cornices and overhead avalanche paths, the morning sun could initiate natural avalanches.
Confidence
Moderate -
Weather Forecast
The work week kicks off with a rather disorganized pattern that is not expected to generate any significant snowfall, but a significant change looks to be in store as a vigorous low approaches the South Coast region Wednesday afternoon.MONDAY: Clear skies in the morning, a few clouds building in the afternoon, freezing level around 500 m, light west/northwest wind, no significant snowfall expected. TUESDAY: Broken cloud cover with clearing in the afternoon, freezing level around 900 m, moderate to strong west/northwest wind, trace of snow possible.WEDNESDAY: Overcast, freezing level around 700 m, potentially strong to extreme south/southwest wind, copious amounts of precipitation possible, but the latest model run shows about 15 cm of snow. Stay tuned for more details.
Avalanche Summary
No new activity to report from Saturday. The new snow was reactive to skier activity on Friday, producing small (size 1) dry loose and storm slabs. See this MIN report that talks about storm slabs 10 to 40 cm in depth here.
Snowpack Summary
Around 30 to 40 cm of storm snow fell on Friday and another 10 to 15 cm of snow fell Saturday night into Sunday. Both of these storms had strong southerly winds. All of this snow fell on previously wind-affected surfaces and a sun crust on southerly aspects. The new snow may not bond well to these surfaces and could be reactive to both natural and human triggers.A hard rain crust that extends into alpine terrain is buried about 60 to 100 cm. Reports suggest the snow has a poor bond to the crust with test results showing sudden planar characteristics and a Rutschblock 2 (the whole block failing after standing on it). Monitor the bonds of the new snow as well as the bond of the snow directly above the buried crust. There are no substantial layers of concern below the crust.Also make note of cornices at ridgeline. Variable winds in the past month have produced cornices on all aspects. They will become touchier as they grow in size, as temperatures rise, and as the sun packs a strong punch on clear days. Stand well back of them!
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.
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.