Conservative route selection, group management and terrain use are needed today given the elevated avalanche danger.
Weather Forecast
The storm continues through today bringing another 10cm+ to alpine elevations along with moderate SW winds. Freezing levels are expected to rise to 1800m today making for moist snow conditions at lower elevations.
Snowpack Summary
Another 7cm of snow at 1900m overnight. 70cm of storm snow overlies the Feb 27 interface which is a crust on solar aspects, and surface hoar/stellars on northerly aspects. Lee slopes feature large cornices with reactive windslabs downslope. Feb 10th surface hoar/crust is down 100cm+ and has been unreactive to tests. Moist snow below 1900m.
Avalanche Summary
A widespread avalanche cycle occurred yesterday mostly in the size 2-2.5 range. These slides were moist and were running to mid run out in most cases. The avalanche cycle is expected to continue today with freezing levels rising to 1800m, 12cm of snow forecast for higher elevations and moderate SW winds.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
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.