Human triggering is still possible in steep and unsupported features. A "Pineapple Express" is forecasted for Thursday night that will bring extreme SW winds and above freezing temperatures. Watch for instabilities associated with the warming trend.
Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain
Weather Forecast
A mix of sun and cloud is expected on Thursday with temperatures warming to -5 in the alpine. A strong pacific front will enter the area some time on Thursday night or Friday morning. This front will bring above freezing temperatures and extremely strong SW winds. Light precipitation is also expected. Freezing level will climb above 1900m on both Friday and Saturday.
Avalanche Summary
Nothing new today, but observations were limited.
Snowpack Summary
Soft slabs are prominent in lee and cross-loaded features at 2300m and above, and remain sensitive to human triggering in steep and unsupported features. In high alpine areas hard slabs are also prevalent. Buried wind slabs formed in late January are found 20 to 50cm deep in the alpine and high treeline areas and are still possible to trigger especially in shallow snowpack regions.
Problems
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.