The NE wind event caused extensive wind loading - and damage! - in the mountains from Croy Canyon/Hailey to the northern Sawtooths. Wind effects were most pronounced in the Boulder Mtns and southern Sawtooths. We observed significant natural avalanche activity in the Boulder Mtns. All activity was on generally west-facing slopes (thin snowpacks) and appeared to predominantly fail on persistent weak layers (likely facets/depth hoar) in the lower half of the snowpack, all in wind loaded areas. We did not see activity except in the Boulder Mtns, but we weren't able to see as much recently wind-loaded terrain (NW-W-SW-S) aspects in other mountain ranges. We could not see much in upper and middle elevations in the Pioneers, but we received reports of significant avalanches that occurred yesterday on west aspects in the Pioneer Mtns near Grays Peak.
Increasing high clouds in Sawtooths by 1 PM. Variable N winds, gusty in favored locations.
Eagle Creek Headwaters
|D2||U||N-Natural||Slide was over 500' wide, spanning W-SW-S aspects, failed in wind-loaded area well below ridgeline. It appeared to fail on a weak layer near the middle of the snowpack.|
Easley Peak area - east of the peak
|D1.5||N-Natural||Slide failed in wind-loaded area well below ridgeline. Blown in, likely happened early yesterday.|
Gladiator Creek - towards Senate Ck
|D2||N-Natural||Slide noted in public observation today. Narrow slide (about 50'), failed at ridgeline on deeper layers in snowpack. W/SW aspect. First spotted yesterday afternoon.|
Cherry Creek - off Spring Ck/Cherry Ck ridge
|D2||N-Natural||Slide was 150-200' wide, failed on persistent layers in the lower half of the snowpack.|
Williams Peak - Sawtooths
S near summit
|D1.5||N-Natural||Hard to tell whether a wind slab or loose snow avalanche, size D1.5-2. Occurred on S-SE aspects in wind-loaded terrain within 300' vertical of the summit. Unsure on timing, but it appeared to be recent.||None|
Williams Peak area - Meadow Creek bowl
|D1||L||I-New/Old Interface||N-Natural||Small sun-induced loose snow slides on E-SE aspects in rocky, wind-loaded, alpine terrain in Meadow Creek Bowl.||None|
Driving obs, no terrain open or closed.