Fresh windslabs growing on weak sugary facets may be surprisingly widespread Thursday. I'd be taking a cautious approach if there's more than 10 cm of new snow.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
A disturbance, not really a storm, is approaching overnight Wednesday and moving out Thursday.WEDNESDAY NIGHT: Increasing clouds becoming overcast. Moderate but gusty southwest winds. Temps remaining cool; around -10 C. New snow around 5 cm, maybe as high as 15 cm.THURSDAY: Cloudy, Moderate but gusting strong southwest winds. Alpine temperatures continue in the range of -8 to -12 C. Little new snow with the exception of localized, short-lived, but potentially heavy snow showers delivering up to around 10cm.FRIDAY: Mix of sun and cloud. Possible flurries but not much accumulation. Moderate southwesterly winds. Alpine high temps to around -5 C.SATURDAY: Mostly sunny. Light westerly winds. Alpine high temperatures to around -5 C. No new snow.
Avalanche Summary
Loose dry avalanches, aka sluffs, are reported running in the weakening faceted snow. Normally this is a "good skiing" avalanche problem of no real concern; however, they're growing in size and approaching size 2 (big enough to injure or bury a skier). A couple of small wind slabs were also reported. Both of these will be old news with incoming new snow and wind: wind slabs are expected to be widespread and possibly larger in the next couple of days.
Snowpack Summary
A mix of hard and soft wind slabs can be found in open alpine terrain, while pockets of soft snow can be found in sheltered and shaded areas.Sun crusts are found on south-facing slopes.There are potentially three layers of surface hoar in the upper snowpack. One is down 30-50 cm, another is down 40-80 cm, and the last one is down 80-120 cm. These layers have been most prominent and reactive between 1600 and 1900 m over the past month. Mid pack is faceting and these layers don't seem much of a concern (at least with cont'd cold dry wx regime).The lower snowpack is maintaining strength in deep HS areas.
Problems
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.