Solar triggered avalanches and cornice failures are likely to increase in frequency the next few days as each day will be warmer than the previous days.
Weather Forecast
Monday will be sun and cloud, no new snow, high of 0 C, light SW winds, and 2300m freezing level. Tuesday will be similar, but with 2500m freezing level. Wednesday will be similar but much warmer with 3500m freezing level.
Snowpack Summary
Windslabs are up to 40cm deep. Sun or temperature crusts extend to treeline and continued into the alpine on southerly slopes. Persistent slabs can be found on most aspects at treeline and above. These have been most reactive to large triggers like cornice failures. Below 1,900m the snowpack is going isothermal on a daily basis.
Avalanche Summary
Sunday there was a report of a size 2 slab avalanche on the NE slopes of Lectern, initiating in the alpine and running in to treeline. Also a couple of size 2-3 moist loose avalanches observed in the Icefield's area starting in steep solar affected alpine gullies and running far.
Confidence
Timing or intensity of solar radiation is uncertain on Monday
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.
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.