Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Likely
- Dimensione
- 3
Your main concern is triggering a large and unsurvivable hard slab avalanche that fails on weak faceted snow 2-5'+ deep. This weak faceted snow is a persistent weak layer that formed during our extended dry spell in December and was subsequently buried on January 4th. The initial indicator avalanche of this newly buried PWL was just two days later on the 6th in Main Porter Fork of MCC in SLC with an upward trend of avalanche activity with additional storms the following week. The world fell apart with an Extreme danger on Sunday Jan 14th with widespread avalanches on many aspects and elevations. Over time, this unstable combination has become more stubborn and yet they are no less deadly. Below is an avalanche frequency chart since Jan 6th for all regions.
Beyond all the highlight reel avalanches are some booby-trap avalanches that have recently caught my eye from last Thursday and Friday. These PWL avalanches are well off the ridgelines and in the mid-elevation (some low elevation) bands but still large enough to catch, carry, and bury you. Don't let your guard down. Slope angle is slope angle.