Regions
Northwest Inland.
Hazard will likely increase on south facing slopes during the day due to strong solar radiation.
Confidence
Fair - Due to the number of field observations
Weather Forecast
Monday: Mainly sunny. The freezing level is at valley bottom. Ridge winds are light to moderate from the east-southeast. Tuesday: Mainly sunny. The freezing level is at valley bottom. Winds are light from the SW. Wednesday: A mix of sun and cloud. The freezing level is at valley bottom. Winds are light from the NW.
Avalanche Summary
No new natural avalanches have been reported in the past couple days; however, rider or remotely triggered avalanches, whumpfing, and cracking continue to be reported throughout the region. Keep a close eye on what the sun and wind are doing over the next few days. Small weather inputs could be enough to tip the scales and increase the potential for rider triggering in specific areas (wind-loaded or sun-exposed slopes).
Snowpack Summary
Outflow winds picked late on Saturday and have likely resulted in reverse loading in exposed terrain. 35-90 cm of settled storm snow overlies a variety of old surfaces including weak facets, surface hoar (more predominant at tree line and below tree line elevations), a scoured crust, wind pressed snow, or any combination of these. Whumpfing, cracking, and reports from the field indicate a very poor bond between the new snow and these old surfaces. Recent snowpack tests give easy or moderate "pops or drops" shears on this persistent weakness and show potential for wide propagation. Recent strong winds have transported some of the new snow and formed dense wind slabs on a variety of aspects in exposed terrain.
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.