We made the long drive to Mammoth Mountain this past weekend, where the view was dominated by two 'mammoth' in-bounds climax avalanches.
Given the overall lack of expected avalanche activity following the most recent storm cycle, these two slides were a dramatic indicator that there is indeed a depth hoar layer lurking along the ground on northern aspects in the Sierra.
It's hard for me to feel much enthusiasm for venturing into the backcountry after examining the slides. Hoar layers such as these can persist long into spring. Moreover, they are almost undetectable: buried two or more meters beneath a consolidated snowpack that may otherwise feel perfectly safe.
In fairness, a skier's weight is probably too trivial to trigger slides like these—unless you happen to hit the slab in just the right place. For now, I think I'll avoid skiing steep north slopes in the Sierra backcountry.