Interesting weather makes for interesting problems. Pay attention to steep solar aspects, overhead cornices and glide crack slopes as large temperature fluctuations and a strong inversion persist.
Weather Forecast
A strong temperature inversion persists with temperatures ranging from -20 at 1300m to 3.0 at 2200m this morning. Valley cloud will clear later this morning with no precipitation for today. Ridge top winds will be light SE with gusts to moderate. The temperature inversion is expected to break down Sunday night as a cool upper trough moves in.
Snowpack Summary
Warm temps above 1900m and strong solar input created moist surface snow in isolated terrain. A thin crust has developed on steep solar aspects. On shaded slopes and low elevations 30cm of low density faceted snow sits on a well settled pack. Hard wind slabs exist in immediate lee features in the alpine.
Avalanche Summary
Yesterday there was evidence of loose, solar triggered avalanches. They were up to size 2 and were occurring from steep, rocky terrain exposed to the sun. This week we have also had two skier triggered avalanches from high alpine terrain features, both were sz 1.5 wind slabs. There have also been glide crack releases observed below treeline.
Problems
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.