Northern Gallatin

Toured into Hyalite basin and found evidence of what looked like an older and large slide on Hyalite peak. Intense wind scouring appears to have taken place, or the slide ripped to the ground. Ample evidence of wind loading and stripping throughout the bowl left us with enough evidence to turn around without digging. We skied lower angle trees out of the basin and then toured into Divide basin. We dug a pit on the sheltered shoulder of the typical skin track to divide peak and got an ECTx. Snowpack was well bonded and congruent to the ground on this specific E-NE aspect and slope Snowpack was about 100-145cm deep in total.

Submitted via instagram: "Ectp12 and 22 at 85 and ~25-30 cm (less planar) respectively on S aspect we did not ski and bailed from after initial pit ~300m away in slightly more protected terrain yielded ectN. Was dug adjacent to ~33-35 degree slope. Slope is located near the head of Flanders Basin"

On Jan 2, a natural avalanche released in the gully above Bobo Like in the Flanders Drainage and washed over a pair of climbers. No one was caught or injured. 

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.

Widespread surface hoar in Hyalite observed up to 8200ft, mostly on E and NE aspects 

The snowpack structure has deteriorated on Ellis since the last time I was there a couple of weeks ago, but without loading, it remains generally stable. I am less optimistic about future stability. All slopes were covered by a layer of surface hoar and near-surface facets. Light winds will do little today to disrupt the surface snow. Hopefully we get some wind that beats this layer up a bit before it gets buried. 

We felt that finding instability was unlikely today with ECTXs and ECTNs in the 20s in both our pits.