Recent and wind-drifted snow has added additional stress to buried persistent weak layers increasing the likelihood of human-triggered avalanches in some locations. The danger is greatest on steep, wind-loaded, northerly aspects near treeline and above.

A layer of near-surface facets (NSF) formed during the long December dry spell. This layer is now buried about a foot deep and has been sensitive in recent stability tests. It is especially reactive in areas where the wind has drifted enough snow to form a stiff slab on top. Strong winds over the past few days have made this problem more widespread. Human-triggered avalanches are most likely to fail here first and could be 1-3 feet deep in drifted areas. It is important to carefully analyze any slope you are considering by digging down to see if the poor structure exists. Avalanches triggered on this weak layer could also step down into our second faceted weak layer at the base of the snowpack. Avalanches failing on this layer would be deep, dangerous, and possibly un-survivable.

In the video below, Dave Garcia demonstrates the reactive potential in our primary layer of concern.

Strong winds blowing from the north over the past couple of days have whipped up fresh slabs of wind-drifted snow. The intensity of the winds have created slabs on all aspects down into near treeline terrain or even below. Cross-loading is a factor on northerly facing slopes, and recent drifts will be especially sensitive anywhere they have formed above a weak, faceted layer. Below are some tips for identifying and avoiding wind slabs. Avoid steep terrainn where you can detect recent deposits of wind drifted snow.