Temps stayed warm overnight and conditions will deteriorate rapidly today with another very warm and sunny day. Travel early and quickly in exposed areas; large avalanches may reach their run-outs even when temps are still cool in the valley bottom.
Weather Forecast
One more hot sunny day is forecast. Today will be sunny with a few clouds later in the day. Alpine temps may climb to 15'C with freezing levels to 3000m, and only light SW winds. By Wed expect clouds and isolated showers, freezing levels to 2700m and gusty winds. Thursday will be similar with freezing levels to 2400m.
Snowpack Summary
There was a good overnight refreeze at valley bottom, but at treeline and in the alpine temps stayed above freezing. On solar aspects is moist and composed of multiple crusts, while on sheltered north aspects dry snow can still be found above ~2100m. A 30-60cm slab over a crust on solar aspects and surface hoar on North aspects remains a concern.
Avalanche Summary
Strong solar and warm temps triggered numerous loose and slab avalanches from all aspects other than due North, and elevations ranged from 1800m to 2600m. Most of the wet avalanches were 2.5's but there were a few size 3's, including a size 3 glide crack release on Mt Tupper. Avalanche activity started around 11am and continued into the evening.
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.