Don't let the sun lure you into letting your guard down. Strong solar and warm alpine temps are expected to increase avalanche danger. Avalanches from solar aspects may run full path to valley bottom. Cornices may fail, triggering deep layers.
Weather Forecast
A strong ridge of high pressure will bring lots of sun (adding solar radiation to the snowpack) through the weekend. In addition, a strong temperature inversion is developing. Above freezing temps are expected up to 2500m today, and 3000m on Friday. Moderate SW winds at treeline will ease to light, with strong NW winds loading slopes at ridgetop.
Snowpack Summary
Over a meter of new snow from the last week is settling. It sits on a surface hoar/graupel layer. Strong SW winds have formed slabs in exposed areas at all elevations. Rain below 1300m formed a crust. The mid pack is well settled with the Nov28 surface hoar layer down around 2m where present. The facetted base is showing signs of strengthening.
Avalanche Summary
Avalanches yesterday were from steep terrain, including a size 3. On Mon, over 62 natural and 47 artillery controlled avalanches occurred along the highway. Most size 2.5-3.5. A size 3.5 natural from Dispatchers Bowl traveled 400m down Connaught creek. Artillery triggered a size 4.0 off Mt Green that failed to glacial ice & ran onto the highway.
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.