Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
After three weeks without any precipitation, a few inches of snow finally fell yesterday. Weather stations are showing 2 to 4" of snow equaling 0.1 to 0.3" snow water equivalent (SWE), which is not that much, but at least it's something. In most terrain, this dusting of new snow is unlikely to cause major avalanche concerns. At upper elevations, however, strong winds have drifted the snow into small wind slabs up to 6 to 12" deep. After our extended drought, this will be something to pay close attention to. That cold dry spell created a layer of weak, faceted snow near the surface that will make this fresh layer of windblown snow a little more reactive today.
The most likely place to find unstable snow will be just below ridgelines, on convex rolls, and in steep gullies. You may notice warning signs like shooting cracks or collapsing, but these signs will not always be there, even when conditions are unstable. You may be able to assess the size and sensitivity of these fresh wind slabs by using small test slopes before moving into steep terrain. You can also manage this problem by avoiding steep alpine terrain.
Glide Avalanches: The glide avalanche cycle has not shown any signs of activity in over a week. However, after two months of active glide avalanches, we are left with open glide cracks across the advisory area. While it is unlikely we will see any of these release today, they are notoriously unpredictable. It is always a good idea to avoid spending time below open glide cracks.
(12/24/2025)
We're going to need more than 2" snow to cover up the damage from the December drought, but at least we're moving in the right direction. CNFAC intern Marc Heifetz working on a rescue refresher on Wednesday in the Seattle Flats.
Photo: Andrew Schauer