Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely
- Size
- 2
The snowmobile avalanches on Saturday fit the pattern to what we've seen since the last storm:
- They were located on the north end of the Skyline which received the most snow from the last storm
- They were on slopes of 40 degrees in steepness
- They were on northerly or easterly facing slopes
- The slopes had been loaded by the wind
- They all broke into a "Persistent Weak Layer" of snow that formed in mid December and is now buried by about 2 feet of snow.
If you're getting into big terrain today, ask yourself how many of these characteristics does the terrain have that you're riding in. Human triggered avalanches are again possible today on slopes with these characteristics.
A Persistent Weak Layer is just that. It can "persist" for a long period of time. How long will this layer affect avalanche conditions? It's hard to say for sure, it will depend on how the future storms behave. The good news is that it does not appear to be one of the worst weak layers that I've seen. It is not all that loose and test results in many locations are good. This is also what makes it tricky because it is clearly still capable of producing avalanches.