Warmth remains the primary driver of avalanche hazard as we shift into a more spring like pattern. Minimize your exposure to large slopes if the snowpack is becoming moist or wet.
Weather Forecast
MONDAY: Freezing level starting at valley bottom, rising to 1500m. Light variable winds at all elevations. Trace of snow possible. Broken cloud cover.TUESDAY: Freezing level starting at 500m, rising to 1800m. Light variable winds at all elevations. No significant precipitation expected. Skies clearing in the afternoon.WEDNESDAY: Freezing level starting at 1000m, rising to 2000m. Light NE winds at all elevations. No significant precipitation expected. Clear skies initially, cloud cover building in the afternoon.
Avalanche Summary
Several cornice falls have been reported in the last few days, some of which have triggered avalanches on slopes below. On Wednesday, a rider triggered size 2 avalanche was reported that likely started on the March PWL before it stepped down to the ground.
Snowpack Summary
The recent 10 to 25cm of storm snow was shifted by variable strong winds into wind slabs on lee slopes above 2000m. Cornices are large and touchy in some spots. The new snow sits over a crust which is generally becoming more supportive. Low elevations sport an isothermal snowpack, which is now capped by a refrozen crust.Persistent weak layers in the upper snowpack remain a lingering concern, although they seem to be slowly gaining strength. In the north of the region, the mid-March crust/facet layer is down 40-60cm. The mid-February crust/facet/surface hoar layer, down about 80 cm, may also still be reactive in isolated areas. Weak layers which formed earlier in the winter are also a concern in certain spots.
Problems
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.
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.