The last 3 days have been consistently filled with new reports of small skier triggered and natural wind slab avalanches occurring at upper elevations. Up to 8” of light snow fell last Tuesday and Wednesday with calm winds, then SW winds optimal for snow transport began Friday night and gradually increased through the weekend and into the day yesterday with gusts into the 50mph range. Even though these winds didn’t create the dramatic snow banners over ridgelines that we often see in the Sierra, they resulted in widespread wind slab development at upper elevations. As lighter NE winds are expected thru this morning before dying down even more this afternoon, new wind slab development will become less likely. While the wind slabs that developed over the past few days will become harder and less likely to trigger, they will remain a concern at least thru today, especially with the unknown that some may be sitting on a weaker faceted snow layer or possibly even isolated areas of fragile surface hoar. Take the time to do many small test pits to see for yourself if there are underlying weak layers and to see how these surface wind slabs are bonding. Remember that variability across slopes can be great! Just because one spot looks good, doesn’t mean everywhere on the slope is good. When in doubt, play it safe and choose less consequential terrain.
