23-24
Weak Snow on Saddle Peak
Alex and I began to dip our toes into a Saddle Peak stability assessment. Given the new snow and HIGH danger on wind-loaded terrain in the Bridger Range, we decided early to skip the summit and cross onto the edge of the Football Field from the Bridger Bowl boundary. Upper slopes had fresh drifts of wind-loaded snow and new cornice growth, but there was not as much loading as we feared there might be. We stuck to our conservative plan and skied the "Bitter End" (the closest run to the south boundary of the ski area) down to 8400' elevation before ducking out across the boundary.
The snowpack is thin and weak, with advanced facets making up most of it. Our test results did not reveal obvious instability, just weakness (ECTX). It is unreasonable to apply that same assessment across the Peak. Human-triggered avalanches are certainly possible, especially in areas with thicker slabs of wind-drifted snow (something that is quite common to find on Saddle Peak). Given the very high-consequence nature of the area, we advise patience and conservative terrain choices and decision-making.
Remote Trigger Near Hyalite Peak
We skinned up towards Hyalite peak today to see how the snowpack was adjusting to this new load. While we did see some point release on the canyon walls during our approach, there was no collapsing and minimal wind effect below 9000 feet. As soon as we topped out into the hyalite lake basin, a northerly wind picked up and there were supportable wind drifts scatted about. Got an ECTx on a northern aspect at 9200' before deciding to ascend a 25 degree adjacent slope. About 50' from our pit we remotely triggered two D1 slab avalanches which broke on the roll over 150' above us. Crowns looked between 1-2' and 20-30' wide. The larger of the two ran 100' more or less. Yikes, time to bail! The low angle tree skiing along the skinner was quite nice.
Pebble Creek
115-120 cm HS @ 8250'
Temp in the low 20's. Overcast until at least 3 p.m.
West side of tree trunks snowblasted by wind, both on the south and north sides of the ridge into Pebble Creek.
Experienced whoomphing starting at 8000', midway up the gully, south side of the ridge, where there was some wind deposition. Parallel cracks 10' apart - looked like "stretch" marks. Extensive whoomphing in the saddle and down in Pebble Creek Valley. Ski penetration = knee deep, and trail breaking was a bit of work today. 18" new snow at 8250' and in Pebble Creek. Snow was too deep for turns on mellow slopes, and too much collapsing to go steeper. Occasionally broke through the hard layer, into the hollow below.
Still windy in Pebble Creek (less than 10 mph), but definitely wind scoured. Looked like a natural avalanche on SE facing slope of the ridge to the N of Pebble Creek.
Coverage still slim down towards the highway.
Ski Cut Avalanche Highland Mountains. NE Facing Ridge.
4-6" of new snow. active transport with increasing sw winds. NE facing ridge. 9200'.
Remotely Triggered Avalanche on Henderson Mountain, Cooke City
On the west side of Henderson Moutain, while ascending a low-angle slope toward a known avalanche path, we experienced several collapses. Halfway up the slope, Ian noted snowballs rolling down the hill and around the corner, we could see the debris that had come from the steep terrain above. We had a clear view of this slope near the snowmobiles and it had not avalanched when we began ascending. At some point from several hundred feet away, we remotely triggered the slope. The avalanche was ~150' wide, 2' deep and ran almost to the road. Across the gully, we could see large cracks but the slope did not avalanche. Above, cracking and collapsing continued and we got a view into the upper part of the gully and saw another crown of an avalanche that likely happened at the same time as the slope below.
Natural Avalanches north of Cooke City
While riding north of Cooke City we noted many natural avalanches on east, west, and south-facing slopes at all elevations. Crowns ranged in depth from 1-2'. Most of these avalanches were not side very wide but several were including, Crown Butte, Henderson Mountain, and Miller Ridge. All of these avalanches happened near the end of yesterday's storm.
Small Rider Triggered Avalanche in Cooke City
A small avalanche was triggered from the flats 100' away by a rider as they were getting their snowmobile unstuck.
Widespread cracking on Henderson Mountain. Photo: GNFAC