Expect freezing levels to creep up throughout the day. Failing cornices could trigger large avalanches running to valley bottoms. Watch out for what's above your head.
Weather Forecast
THURSDAY: Freezing levels creep up to near 3000m in the late afternoon, cloudy in the morning then clearing throughout the day, light-moderate southwest ridgetop winds. FRIDAY: Freezing levels soar to 3500m, sunny, light westerly ridgetop winds. SATURDAY: Freezing level 2700m, sunny, light westerly ridgetop winds.
Avalanche Summary
No new avalanches were reported in this region on Tuesday.
Snowpack Summary
Cornices are large, fragile, and could trigger deep slab avalanches running to valley bottom. 10cm of recent storm snow with moderate westerly winds have created thin wind slabs on lee aspects in the alpine and open treeline. Deeply buried weak layers in the mid snowpack and near the ground still have the potential to wake up and become active with a rapid warm up. While unlikely, releases on these deeply buried weak layers would result in very large avalanches running to valley bottoms. Glide cracks are widespread, active, and best avoided. Low elevation and thin snowpack areas have become isothermal.
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.
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.
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.