VARIABILITY is the main issue right now. Large variation in snow depth across terrain from 20 cm to 2+ meters will make avalanche hazard tricky to assess. Wide swings in temperature will change a solid snowpack to a very weak one.
Weather Forecast
A weak disturbance in a NW flow will bring mostly cloudy skies today with a chance of convective flurries. A ridge is expected to move in late this afternoon, with clearing skies and rising freezing levels. Note that the wind direction could cause reverse loading in the alpine and along ridge features. Dry conditions are expected on Wednesday.
Snowpack Summary
In the alpine, due north aspects are maintaining dry snow conditions over multiple temperature crusts. Solar aspects have more crusts, and daytime warming is creating sticky, wet, and/or crusty conditions. At lower elevations (below 2200m), the snowpack is largely isothermal, but overnight re-freezing provides firm travel early in the morning.
Avalanche Summary
Large slab avalanches continue to be observed on all aspects. Many of these are associated with cornice triggers, and are failing on the April 3 surface hoar/sun crust PWL, down 40 to 80 cm. Several reports of moist surface sluffing from rocks, or from skiers, have been received. Moist or loose snow avalanches will be very temperature dependent.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Wednesday
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.
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.