Forecast new snow and wind will increase the avalanche danger. Snow fall amounts are uncertain on Tuesday; watch for developing hazard during the day.
Confidence
Moderate - Freezing levels are uncertain on Tuesday
Weather Forecast
Overnight: 5-8 cm of new snow above 1000 metres combined with moderate southwest winds. Tuesday: 10-15 cm of new snow during the day combined with strong southwest winds and freezing levels around 1300 metres. Wednesday: Another 10-15 cm of new snow combined with light to moderate southwest winds and daytime freezing levels around 1300 metres. Thursday: A brief ridge of high pressure should bring clear skies and strong solar radiation.
Avalanche Summary
Explosives control work on cornices produced some large chunks up to size 2.0 on Monday. Ski cutting also resulted in avalanches size 1.0 on Monday.
Snowpack Summary
Forecast stormy conditions are expected to add to the recent storm slabs. At about 2000 metres and below, the storm snow lies above a crust (March 22) that formed last week. Beneath this older storm snow, an older rain crust that was buried around March 15 is now about 80-100 cm deep. The mid-February crust/facet layer can still be found at the upper end of treeline and into the alpine. This interface is now generally 125-165 cm deep but may present at the surface or up to 250 cm deep in heavily wind affected terrain. Although there is growing confidence in this layer becoming dormant, continued caution is warranted while our recently formed storm slabs remain triggerable. A big enough storm slab or cornice release in the right location may have the potential to coax this layer or the shallower March 15 crust layer into reacting.
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.