Rain at low elevations, and heavy snow in the alpine is rapidly adding load to the snowpack. The upper snowpack was already moist from warm temps and is expected to be easily triggered by light loads. Be cautious until freezing levels lower.
Weather Forecast
Freezing levels are expected to stay around 1800m but should drop to 1100m overnight. A mix of rain and snow will add load to the moist snow at low elevations, and ~10cm of heavy snow in the alpine. SW winds will continue to load lees. Friday and Sat temps should have lowered to -7'C in the alpine with isolated flurries and freezing levels at 1400m
Snowpack Summary
Freezing levels rose yesterday and hovered around 2000m overnight. At 1900m ~7cm fell mixed with 3mm of rain, at 1300m we got 5 cm of snow and 3mm of rain. At TL and above ~15cm of snow sits on suncrust on solar aspects and surface hoar in areas sheltered from sun and wind. The top 20-40cm of snow is moist on all aspects to TL.
Avalanche Summary
Yesterday, moderate S'ly winds loaded lee aspects and triggered size 2 avalanches from paths with steep N facing start zones. On N aspects in the alpine, stubborn windslabs were reported to be reactive to skiers producing size 1 avalanches. At low elevations, loose wet avalanches were observed this morning up to size 2.
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.
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.
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.