Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Likely
- Dimensione
- 1–2
Weak snow left from December is buried 1-3 feet in most areas on Togwotee Pass. This includes all aspects (sunny and shady) at just about all elevations that you may be riding. Upper elevations have more snow and a thicker slab has settled and stiffened over the last few days as a result of warm temperatures and wind. It is becoming more difficult to trigger an avalanche by collapsing the weak layer under this slab. Impacting and collapsing the weak layer is most likely to occur if you encounter an area where the snowpack is thin or if you happen to trench down with your sled in just the wrong spot. It is becoming less likely to trigger an avalanche, but given the widespread nature of the December drought layer, these avalanches can still propagate long distances. The Barber’s Point avalanche that occurred on Saturday is a great example of how far these avalanches can propagate across slopes.
Give steep slopes and runout zones a wide margin. With a little new snow overnight and warming temperatures, conditions can be more sensitive during the heat of the day. Remotely triggering an avalanche from above, below or next to a slope is possible. Watch out for cracking and collapsing as you travel, but with this tricky snowpack, obvious clues do not always present and it’s possible to trigger an avalanche without seeing any clues of instability. A wide safety margin is your best bet. Increase your margin by riding low angle slopes, avoiding overhead avalanche terrain and giving terrain traps a wide berth.
A nautral slab avalanche that occured in steep, thin terrain.