Loose snow avalanche Hyalite Canyon, Bobo Like

Hyalite - East Fork
Northern Gallatin

At about 10 AM I was belaying my partner on the first pitch of Bobo Like in the Flanders drainage of Hyalite Canyon.  We heard a low rumble and a couple seconds later we were engulfed in snow that poured out of the the pitch 2 gully, and seemed to keep coming for about 5 seconds.  My partner, who was on lead, was lucky enough to be at the base of the vertical ice of p1, so the snow mostly went over his head.  I was off to the side and close to rock at the base and was engulfed in loose snow, but not buried or injured.  We continued up afterwards.  When I was at the top of the second pitch, belaying my partner up, another small loose snow avalanche came down as river of snow, passing me as I hugged the anchor, and washed over my partner while he was on the pitch.  We were fortunate to have both been in positions to handle these avalanches without incident or injury.  In retrospect, the clear day and blasting morning sun likely loosened the snow above the gully and funneled it all down onto us.  After the first avalanche, the sun must have kept moving onto new slopes above, releasing more snow.  Even with a moderate danger level in the avalanche report for the day, with natural avalanches unlikely, we happened to find ourselves in a very specific scenario, with morning sun and a dangerous terrain feature, that still put us at risk.  Hopefully we will use this experience to improve our assessment of risk, terrain, and evolving conditions in the future.

Number of slides
Number caught
Number buried
Avalanche Type
Loose-snow avalanche
Natural trigger
Slab Thickness units
Single / Multiple / Red Flag
Single Avalanche
Advisory Year