Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3
Recent Avalanches: The last significant avalanche cycle was during the Thanksgiving storm, about 11 days ago. Since then, we have seen continued glide avalanche activity throughout the area.
The cold and clear weather has taken hold and doesn't want to let go. During this period of prolonged high pressure, our main concern is several lingering buried surface hoar layers that formed in November and are buried up to 3' deep. Triggering an avalanche on these weak layers is slowly becoming less likely, but there is a reason they are called persistent weak layers. They can sit in the snowpack for weeks or longer and still cause large avalanches with no warning signs.
These weak layers are only a concern above 2500', but that is also where the good snow conditions are. Digging snow pits can be a good way to identify and assess locations where these weak layers still exist. However, the signs can be very subtle, and even avalanche professionals can get unreliable information from digging pits with this type of weak layer. The best way to avoid the problem entirely is to stick to simple terrain, with low angle slopes and away from any terrain traps that could cause a deeper burial in case of an avalanche.
Wind Slabs: So far, it seems like Turangain Pass has avoided the brunt of the outflow winds. But these winds can be highly localized, so it is important to look for active wind transport and be aware that wind slabs up to 1' deep could be easy for a person to trigger near ridgelines or convex features.
