Sunshine has a dramatic effect on the snowpack at this time of year, warming and weakening it very quickly.
Weather Forecast
High overcast will spread through the area, bringing scattered flurries and reducing the overall punch of the sun today. A more organized front will arrive Thursday, bringing as much as 20mm of precipitation, with freezing levels at 1400m and moderate to strong westerly winds. Winter ain't over yet...
Snowpack Summary
Temperature crust on solar aspects, the Mar 22 down ~ 30-50cm, the Mar 13 crust down 75cm, the Mar 2 down 1-1.5m. On north aspects the upper snowpack consists of settling storm snow to about 1600m below which there will be a crust. The Feb 10 surface hoar crust layer is down 2m.
Avalanche Summary
As expected, the warm temperatures and high solar input created numerous moist, loose avalanches up to size 2.5 on S and W aspects yesterday, mainly at tree-line or below. On Monday, there was a skier controlled avalanche, size 1.5 on an immediate lee feature of a ridge top, Nw asp, 2420m, down 20cm on the March 22 crust, 100m long and 25m wide.
Problems
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.
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.
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.