Ted was cruising around the North Slope near Moffit Basin and the Whitney Environs noting multiple large, and destructive persistent slab avalanches from the recent cycle that occurred this week. See more from his travels, here.
On northwest through east aspects at all elevations, our January Drought Layer (JDL) is buried 1-3' deep and well preserved by our most recent set of storms that exited the region this past week. The faceted snow that is buried is extremely weak and has been coming to life with the recently received 2-3' of snow and up to 3" of SWE, in some areas across the range. We saw a widespread natural avalanche cycle across the range, along with tons of human-triggered slides that have been reported over the past few days. Similar to what we have observed, today's persistent slab avalanches will be large, up to 4' deep and breaking multiple football fields wide across slopes wrapping around features of terrain.
This problem is widespread across all elevations on the north half of the compass -- When I think of bullseye terrain where I could trigger a dangerous slide, places like Currant Creek Peak, Heber Mountain, Mill Hollow or Humpy Creek come to mind. Sure, we can trigger the big slope that has an obvious hazard to us as riders, but my greater concern is the benign slopes, that we usually ride right past or don't give much thought too. Im thinking cut-banks, gullies, and small terrain features that enhance the consequences if caught in even a small avalanche.
Yesterday, we had lots of obvious clues and red flags pointing at this hazard. Large cracks shooting out hundreds of feet in front of our rigs as well as several booming, audible collapses on the north half of the compass. These avalanches are deadly, tree-snapping, don't get to go home to your family slides. Unfortunately, we are going to be dealing with this problem for a while and have to understand that avoidance is the only, and best tool for the job, when dealing with persistent weak layers.
Above are the types of slopes we are concerned about today -- Wind-sheltered, benign, and waiting for a trigger. On Thursday, a savy crew of riders were working their way up Mill Hollow, and while traveling in the flats by the creek on the other side of the drainage, triggered the road cut 2' deep and nearly 750' wide stacking up an impressive amount as seen by the trench carved through the debris -- Thanks for sharing JJ!