Big Jay

Quick report

No signs of instability all day despite new storm that had been Mn transported by north and then west wind in the last 24h. Leery of wind slab development up high, we chose terrain that was sheltered, far below ridgeline. Numerous hand shear tests showed non-planar shear of the new storm snow (10-25 cm deep), and skinning on the new snow produced very localized and isolated cracking that suggested low propagation potential. This was my second run in the same zone. I expected to ski cut this slope but overestimated: 1) the speed I would carry to cut the slope, and 2) snowpack depth on this convex rollover/cliff. I did suspect the slope had potential to produce a D1 avalanche, and made the decision to ride knowing that the terrain below was fairly open and filled with deep, soft snow. Looking back at the photo and where my track is relative to the crown I seem to have hit an anomalously thin spot in the snowpack, and the crown propagated farther back than I thought it could - you can see the crown below my track for as far as I can see in the photo. My experience today underscores the spatial variability in snowpack depth and giving wide birth to steep convexities, even in a backcountry zone that has received a large amount of natural snow and where small avalanches are seldom shared or reported.

Avalanche

Size

D1

Aspect

E

Trigger

AR

Elevation

3150 ft

Snowboarder triggered D1 avalanche on an isolated convex terrain feature. I was carried down on my toeside edge to the base of the exposed bedrock, landing on my feet in the deep snow.