Persistent Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Very Likely
- Größe
- 3
It is imperative that you continue to avoid steep slopes in the higher terrain especially on slopes that face northwest through east. All of the storm snow that's fallen since Christmas Eve has stacked up on top of loose sugary snow. This is what we call a "Persistent Weak Layer" and it does not stabilize rapidly. We will continue to see problems with these faceted layers of old snow for a while still.
Here are clues that tell you things are unstable:
Recent avalanches. You may see some slides that released recently. This is the biggest clue that conditions are unstable.
Collapsing or "Whumpfing" of the snowpack underneath you. This is the loose sugary snow failing when you disturb it. If you are on a steep slope when this happens, it will avalanche.
Trenching or punching through to the ground with your boots. You'll notice that your track will drop deep through the snowpack and trench into very loose snow. If you step off your machine or skis or snowboard, you'll punch right through to the ground in many areas. Grab a handful of snow from down deep and you'll notice it's just like sugar. This is the dangerous Persistent Weak Layer of faceted snow.
Wind. Strong ridgetop wind today will drift more snow. This increases the danger by continuing to add weight on top of the Persistent Weak Layer. Watch for plumes coming off ridges and avoid places where the snow is getting deposited.
