The sun is triggering both recent windslabs, and cornices today, both are touchy, use caution today.
Weather Forecast
Sunny with cloudy periods, and flurries possible. Light winds from the SE with gusts to 40kph. Freezing line rising to 1900m today. Tonight flurries with 6cm and light S winds gusting to 45kph. Saturday and Sunday bring more snowfall, and gusty winds, with the freeze line rising to 1800m on Saturday.
Snowpack Summary
Windslabs in the Alpine and Treeline are touchy, with surface hoar sitting on thick sun crust. Snowpack test results at Mt Fidelity showed these slabs were ripe to trigger and propagate on a S aspect. Ridge top cornices are weak right now and can trigger deeper layers in the snowpack causing larger avalanches. Sun today will increase hazard levels.
Avalanche Summary
A natural avalanche cycle is currently underway, with numerous sz 2-3's from recent snowfall and strong to extreme winds. A large sz 3.5 from a NE aspect on Parson's Peak in the Bonney drainage was triggered by a cornice fall early this morning and dug down through the entire winters snowpack and in places to glacier ice.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
Problems
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.
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.
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.