Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1–2
You'll find the widespread wind loading on a variety of aspects. Observers and ski patrol found reactive slabs and snow pits near and above the treeline two days in a row and winds will maintain these dangerous conditions through Friday. Old, large slabs linger on westerly aspects from Wednesday's E wind event while fresher slabs continue forming with the current SSW winds. Above treeline, these avalanches will be large, widespread, and easy to trigger. Avoid all potentially wind-loaded slopes steeper than 35 degrees at these elevations. Near treeline, danger is moderate, but your travel will be much more nuanced. Three weaknesses that lie above the Christmas crust have us concerned (see the discussion). Wind drifts will create the slab necessary for propagation along these weaknesses. What this means for you is that you'll want to be especially cognizant of where slabs have drifted more thickly in this elevation band. Check for firm over weak snow layers and active wind loading; pay attention to whumphs or shooting cracks; frequent hand shears or test slopes can help you identify mid-storm slabs. Steer around steep and potentially wind-loaded slopes, particularly in areas where you find warning signs. Incremental loading of these weaker snow layers means that they may not reach the threshold for human-triggered avalanches at once, but we think that you can trigger avalanches on these layers in steep, wind-loaded pockets.
At lower elevations, rain on snow may produce small wet loose avalanches, but in the upper portion of this elevation band, you could find isolated wind slabs.
(1/5/2023) Small shooting crack, undercut by ski track. SW aspect, 6300’. Photo: Ryan Matz
