Recent snow over this past week should keep avalanche conditions in the forefront of your mind. Good skiing can be found on north aspects.
Weather Forecast
Overnight on thursday we may see up to an additional 15cm of snow and another 5-10cm on Friday. Winds are forecast to be light with freezing levels are 2000m. Start early while there is still a good freeze and be home early.
Avalanche Summary
A few recent sz 3 avalanches have been observed failing to ground initiating in Alpine terrain on N through E aspects. Cornices are large, and are the suspected trigger in these avalanches. There has also been loose wet at lower elevaitons, and loose dry in Alpine terrain from steep unskiable features.
Snowpack Summary
20-30cm of snow has fallen over the past few days (23-27th of April) with warm temperatures and generally light winds. This new snow is settling rapidly at lower elevations and more slowly in alpine areas. Expect to encounter a series of melt freeze crusts on solar aspects up the 3100m and dry powder snow in alpine terrain on northern aspects. At 2200m and below, expect to encounter widespread surface crusts that will be supportive in the morning and less so in the afternoon. On solar aspects, watch for the new snow forming thin slabs or loose dry slides on the underlying crusts that react quickly to a skiers weight.
Problems
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.
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.