Persistent Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Likely
- Größe
- 2
North Slope local Ted Scroggin, was in the East Fork of the Bear River zone and noted multiple persistent slab avalanches at mid and upper elevations from the recent cycle that occurred earlier this week. See more from Ted, here.
Strong winds blowing from the southwest coupled with recent storm snow create cohesive slabs and wind-drifts that sit atop a persistent weak layer of near surface facets that formed over the long stretch of dry, January weather. On mid and upper elevation slopes with a northerly component, this weak layer is buried anywhere between 1-3' beneath the surface, is reactive to our additional weight as a rider, and can be triggered remotely, or from a distance.
I am avoiding steep and wind-drifted slopes today on northwest through east aspects, especially in rocky and thin areas that could be trigger points, where the snowpack is more susceptible to our weight. Be on the lookout for cracking, and listen for collapsing as your traveling today -- These are obvious clues and red flags of this avalanche dragon. Remember, there is a lot of weak snow buried beneath the surface, but areas out of the windzone where snow has not been drifted by the wind lacks the final ingredient needed to create a slab avalanche -- A slab! And don't forget, you can always avoid the avalanche all together by riding slopes less than 30° without any steep terrain above or adjacent to you.
Craig was moving around Upper Weber Canyon taking a look and giving us some insight on our current set-up, obvious red flags to look for, and what to expect down the road when the storm-tap turns on again and we start to stack it up. See more from his work yesterday, found here.