Even short periods of solar heating or rain may cause an increase in the hazard beyond the posted Danger Ratings. Be conservative Tuesday as the snowpack will be stressed by the highest freezing level encountered yet this season.
Weather Forecast
Freezing level rose to 2800m Monday. With a poor overnight recovery forecast, and more solar heating into Tuesday, the snowpack will be weakened further. Overnight rain with snow above 1800m and strong winds will add heat at low elevations and windloading above for Wed when more sun is expected. A better recovery is seen Wed Pm with more sun Thurs.
Snowpack Summary
Surface crusts on East through West aspects have formed with the daily heating pattern and rain below 1700m. Down 30 to 40cm on shaded aspects a shear persists on the 0325 interface. The strong March crusts are found down 70 to 100cm on all but North aspects above treeline and overlie the Feb facets that remain weak at about 1m above the ground.
Avalanche Summary
Widespread superficial loose moist activity has been seen over the last few days as a result of heating. On Sunday heating was strong enough that one of these triggered a 40 cm deep slab on an E aspect. Expect this activity to increase Tuesday. On shaded aspects and at higher elevations a few windslabs have been seen following modest new snow input
Confidence
Timing or intensity of solar radiation is uncertain
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.
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.
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.