Fresh snow accumulated at upper elevations along with strong variable winds. Use caution around ridge crests and lee terrain features, where deposits will be most reactive and may also hide older, recently formed wind slabs.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
SUNDAY NIGHT: Cloudy with clear periods and isolated flurries, trace snow / west wind, 15 km/h / alpine low -10C / freezing level valley bottomMONDAY: Cloudy with increasing sun / southwest wind, 10-15 km/h / alpine high 0 C / freezing level 1600 mTUESDAY: Mix of sun and cloud with isolated flurries, trace to 4 cm snow / southwest wind, 25-40 km/h / alpine high +1 C / freezing level 1800 mWEDNESDAY: Mix of sun and cloud with isolated flurries, trace to 4 cm snow / west wind, 30-45 km/h / alpine high +2 C / freezing level 1900 m
Avalanche Summary
On Thursday, a couple natural and machine triggered storm slab avalanches 20-40 cm deep and up to size 2.5 were observed on east facing alpine slopes.On Tuesday, a small (size 1) slab avalanche 30 cm deep was remotely triggered by a skier from 80 m away on a northeast aspect at 2250 m. A layer of small surface hoar below the most recent snow may have been the weak layer. Additionally, several loose wet avalanches up to size 1.5 were triggered on solar aspects throughout the day by strong solar radiation.
Snowpack Summary
Up to 15 cm snow accumulated above 1200 m Sunday along with westerly winds. On most aspects this covered a melt-freeze crust; on north facing slopes in the alpine, new snow fell over the recent 20-50 cm wind-affected snow and surface hoar in isolated locations. Older wind slabs sitting on surface hoar might still be sensitive to human triggers.Below treeline snow is disappearing rapidly.
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.
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.