Natural avalanches and cornice failures are expected today due to strong solar radiation.
Weather Forecast
It's looking like a beautiful bluebird day; clear skies, mild temps with the freezing level rising to 1500m, and moderate westerly winds are expected. This will be the strongest punch of sun the snowpack has received, and it will increase avalanche danger today. Unsettled conditions will return tomorrow, with increasing cloud and up to 10cm of snow
Snowpack Summary
A new crust formed yesterday on solar aspects below 1600m. 10cm of light snow overlies a rain crust to 1800m and settled snow and windslabs above. The settled storm slab is gaining strength. The Feb 12th PWL, now down over a meter, is of most concern on solar aspects where is overlies a crust, and on slopes where it has not yet avalanched.
Avalanche Summary
No new avalanches have been observed in the last 3 days. On a west aspect yesterday, skiers reported moist snow sluffing and snowballing on steep slopes below 1600m. Strong solar today will trigger loose avalanches on solar aspects and likely cause cornice failures, which may step down to deeper layers triggering large slab avalanches.
Confidence
Intensity of incoming weather systems is uncertain
Problems
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.
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.