Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1
Since the last snowfall on Sunday the wind has blown just enough to create some pockets of wind slab that exist at the higher elevations on the lee side of ridges.
A very firm crust still exists out there influencing the surface conditions. The crust is breakable at about 4,000 feet. Near the ridgetops the crust is very firm and supportive. Some aspects have a couple inches of snow over the crust that fell early this week. On lower angle slopes at higher elevations, where more snow fell, this is just enough snow to improve the sliding conditions. Surface hoar is forming on top of everything so we will want to pay attention to the next round of snowfall to affect our region. The main concern today and this weekend is not busting yourself up on this ice crust. Think about uncontrolled slides down a very hard and slippery surface as well as projectile impact if you fall. Ouch.
Since the last snowfall on Sunday the wind has blown just enough to create some pockets of wind slab that exist at the higher elevations on the lee side of ridges.
It looks like we get a couple of sunny days before the next round of weather rolls in on Sunday. Cold, clear nights means that surface hoar will be growing. It was already well-formed and widespread when we were in the Cabinet Moutains yesterday. The ice crust with low density snow over it as well as surface hoar on top is not a good snow structure to support the next accumulation of snow. The new snow will come in cold and therefore will have a poor bond with the surface hoar, see picture below. The ice crust underneath will ensure that any weakness will have a hard and smooth bedsurface to slide on. Faceting is occurring underneath the crust but is not a concern now, see picture below. So, enjoy the sun and stable conditions we have now because it is not going to stay that way for long.