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 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 Coast.
10 to 20 cm of new snow Tuesday will add to the 55 cm that fell over the weekend. The snow rests on a mix of old surfaces and storm slabs may remain sensitive to human triggering. Start with simple terrain and gather info before stepping out.
Confidence
Low - Due to the number of field observations
Weather Forecast
A weak upper trough Tuesday should deliver a good shot of precipitation and wind before a vigorous low makes landfall on Wednesday which has potential to bring significant precipitation. Unfortunately the weather models have not yet agreed on a solution with regard to track and intensity, but there will likely be less uncertainty as we get closer to Wednesday. Stay tuned for more details. TUESDAY: Overcast, freezing level around 500 m, moderate to strong northwest wind, 10 to 20 cm of snow.WEDNESDAY: Overcast, freezing level around 750 m, potentially strong to extreme south/southwest wind, latest model run shows about 10 cm of snow. Stay tuned for more details. THURSDAY: Scattered cloud cover, freezing level around 1000 m, light southeast wind, trace of snow possible.
Avalanche Summary
No new activity to report from Saturday or Sunday. 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 rests on previously wind-affected surfaces and a sun crust on southerly aspects.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.