Lava Mountain

We rode up to the Lava Mountain Overlook to investigate an avalanche triggered by a rider on the ridgeline above a steep, E-facing bowl off the Lava Summit. This avalanche was triggered from a slightly shallower spot on flat ground but with a well-connected hard slab. The resulting avalanche crown ranged from ~3 feet to over 10 feet tall, primarily composed of wind-compacted snow. The west face of Lava Mountain is almost entirely clear of snow (all dirt), and it is pretty clear that that snow was transported onto the E side of the peak, forming a variable depth hard slab. Around a third of the snowpack was recent snow from 1/31 onward. The middle half of the snowpack was composed of rounding NSFs from the January dry spell and everything to the ground below that was weak, faceted snow and depth hoar. The avalanche spanned around 800 feet wide and produced hard results in an extended column test (ECTP29, PST 20/100 End) at the shallowest spot. Areas where this problem lurks in Togwotee are rocky, wind-affected, upper-elevation terrain, primarily on the north half of the compass (W-N-E). 

It is worth noting that the avalanche fatality on 1/.4 occurred on this same layer and was triggered from less-steep terrain. Upper-elevation peaks and cirques that skiers and riders frequent (but are also fewer and farther between than most of the terrain at Togwotee) are surrounded by volcanic rock and variable, wind-affected snow depths. These specific terrain features that are larger (steep planar faces, broad start zones, couloirs, etc) and well-connected above or below you are where you are most likely to encounter this problem. 

Many thanks for this stellar observation so we could go check this out, and please submit anytime you see or trigger an avalanche. It helps us track activity and spatial distribution of weak snow across the ranges.