Crazy warm temperatures on Tuesday. Give the snowpack a couple days to adjust. The cooling trend will help to stabilize.
Weather Forecast
Now until Friday, freezing level will hover around 1800m, temperatures will be seasonal -3 to -6 with good overnight freeze Tuesday night. Expect freeze thaw conditions. Mixed clouds and trace of snow rest of the week.
Snowpack Summary
Tuesday's warm temperatures softened alpine surface snow and weakened lower elevations snowpack making for moist/wet conditions. Slabs will persist at tree-line and above on North-Easterly aspects below ridge crests and cross-loaded terrain. The mid-pack is facetted, new snow interface is a concern along with a decomposed surface hoar down 40cm.
Avalanche Summary
Warm temperatures induced a natural avalanche cycle on Tuesday late afternoon. Size 3's noted in the alpine and size 2's at lower elevations. Highway 93 was subsequently closed in the late afternoon.
Confidence
Timing or intensity of solar radiation is uncertain
Problems
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.