Snowmobile triggered avalanche in Island Park near Mt Jefferson/Sawtelle Peak. Photo: Anon
22-23
Whumpf on Surface hoar at Hebgen
Skinned up to the ridge and when we were almost to the top my partner was out front and triggered a noticeable whumpf. ESE aspect, 8950 ft.
HS = 135
SH at 105 cm, ECTP3
DH at 45 cm, ECTP23
Forecast link: GNFAC Avalanche Forecast for Thu Jan 12, 2023GNFAC Avalanche Forecast for Fri Jan 13, 2023
Unstable Surface hoar at Hebgen
Snowpit Test Results near Texas Meadows
Today on a west aspect around 7,835' in the Bridgers, near the top of Texas Meadows my party had test results of CT28 (SC) and ECTP25 both at 20 centimeters up from the ground. Snow pits my party dug on other aspects in the area had unremarkable results.
Surface hoar growth: Bradley Meadows
Observed widespread surface hoar growth (up to 2mm) along the Bradley Meadows uptrack. E-SE from 7400-7800’.
New Snow and Weak Layers in Lionhead
We rode to ski hill first, and we dug a pit on the NE aspect near the top of the slide path. The HS was 160 cm (5 feet). We found buried surface hoar under the 10-12” of new snow, and we got an ECTN13 on this layer. Next we rode to the old weather station, and the HS was 5.5’. We found the surface hoar in this pit too, but it did not propagate during our ECT. Despite these two results, skiers near Hebgen Lake found the surface hoar layer, and they had an ECTP3 and 6 on that layer. They also noted an ECTP26 on depth hoar near the bottom of the snowpack. Although the surface hoar isn’t propagating on every slope in the Lionhead Range, it is possible for it to propagate on other slopes in the range. With this buried surface hoar and facets near the ground riders and skiers should continue to carefully assess the snowpack before stepping out into steeper terrain.
testing from Clarkston
We skied up to 9230 on a south slope of Miller Ridge in sheep creek basin. Intermittent clouds and sun, no wind. Much wind affected snow, cross loading. 2-4 inches of fresh snow. HS at 9000 was 100-110cm. Started finding wind slab on rotten base at about 8900 then at 9200 where slope steepened we observed 3-5 foot shooting cracks and turned around. Slope was 27-35. Had climbed thru whitebark regrowth from 88 fire.
Back down at 8400', snowpack was very shallow and temp. was 32 degrees.