Lionhead Range

We rode into Yale Creek just south of Sawtell peak in the Centennials. Thin snowpack that is mostly faceted. There was a slight rain/mist the night before and again in the afternoon with warm air moving into the area ahead of the approaching storm. The rain/mist created a zipper crust on top of the snowpack.

The snow under that zipper crust is faceted and weak. It will be the primary weak layer once a slab forms on top.

We rode out of the Buttermilk Trailhead to the old Ski Hill at Lionhead with Gallatin County SAR, Fremont County SAR, and local snowmobile guide from West Yellowstone for our annual West Yellowstone Avalanche Fundamentals class.

It snowed lightly all day without much accumulation (maybe an inch). Winds were stronger than I anticipated, but weren't moving much snow at 8000.' I suspect there was a bit more transport at higher elevations along the ridgeline, but there just isn't much soft snow available for transport. Isolated instability is tied to wind loading. At the Ski Hill breakover, we dug 40 people worth of snow pits. In a couple of them, there was just enough wind loading to get propagating results (ECT16-ECTP24) on basal weak layers. 

Recently, buried surface hoar and near surface facets didn't have enough new snow on it to cause problems, but it was preserved under 1-2" of snow. 

Just an initial look at low elevation snow around some of the ice climbs.

8" of new snow at the Grotto Falls TH. 
 

I couldn't find any surface hoar that was buried by last night's snow, but I'm sure it's out there. Doesn't really matter because there's plenty of weak, faceted snow that was the previous snow surface.

The new snow is all fluff and not a concern at lower elevations in Hyalite. Perhaps it could be enough of a load and enough of a cohesive slab at higher elevations where more snow fell. 

For now, things seem mostly stable, but that will change quickly with any amount of wind. 

With another day of high pressure and clear skies, Alex and I rode into Lionhead and parked the snowmobiles at the top of Ski Hill. The coverage in and out was decent for this time of year, but thin cover and sharks abound. We dug a snowpit at the top of Ski Hill (8150')  and then toured up to the south end of Lionhead Ridge and dug there (8650').

Our snowpits told very similar stories of a weak, layered snowpack from top to bottom: glittering surface hoar on top and different variations of facets to the base. In both snowpits we got ECTN's on interfaces between faceting snow. In our upper pit, we noted a more cohesive slab on top, but it was just not enough to get propagation in that spot. 

As we skinned up the ridge, we also noted very isolated collapses, one to two feet from the tips of our skis. But overall, there were no signs of instability, just weak snow, growing weaker by the day. 

Until the next round of snowfall, our main hazards continue to be the rocks, trees, and stumps just beneath the surface.  

WE facing snow at 8100 ft Cabin Ck

Cabin Creek snow cover