Persistant slab avalanche on Fisher that broke near the ground. Photo: GNFAC
We rode out to Lulu Pass to look at the few avalanches that were reported yesterday on Henderson and Fisher Mtn. Today we did not see any avalanches that weren't previously reported, other than one small, but thick wind slab on south facing slope of Scotch Bonnet (photo). At least the avalanche on Fisher and one on Henderson broke near the ground (pics attached). Some slides were heavily refilled by drifted snow, so it was hard to tell how deep they broke.
Yesterday I saw a wide slab avalanche up on west Woody Ridge from town (photo attached). It happened late on Wednesday or overnight during or after the strong winds and snowfall.
We dug a pit on a north-northeast facing slope below Fisher Mtn. (on Rob's Knob). Snowpack was just over 3 feet deep with a stripe of surface hoar in the middle. Generally 1F to Pencil hard slab above the SH. Facets near the ground were 2-3mm and rounding. We had ECTP22 on the surface hoar and ECTN22 and PST 25/100arr.
Despite the generally hard and rounded facets near the ground, recent avalanches are a sign that those are a problem in addition to the surface hoar.
Clear and mostly calm today. A few rollerballs on southwest aspects.
Overall, the recent avalanche activity is a sign that the early season weak layers are a problem to watch going forward. Danger and likelihood of avalanches may decrease in the immediate future with a break from loading, but we need to be thinking about these layers when future storms add up.
From email: "Maiden Voyage to Goose Lake for the season today. Lots of wind drifted snow everywhere and challenging riding conditions. Performed Stability test on shoulder of Mount Fox NE facing slope at 10,300'. HS 180cm. ECTP2 40cm down on Buried Surface Hoar. ECTP 23 90cm down on MFcr with 1-2mm Facets. Saw several recent wind slab avalanches in steeper windloaded terrrain around Goose Lake, but limited activity was seen on Henderson. Lots of co/cr while touring on Mount Fox. D2 avalanche on east facing Mount Fox that appears to be on the SH layer, triggered by a cornice drop."
D2 avalanche on east facing Mount Fox that appears to be on the SH layer, triggered by a cornice drop.
Photo: B Zavora
From email: "Maiden Voyage to Goose Lake for the season today. Lots of wind drifted snow everywhere and challenging riding conditions. Performed Stability test on shoulder of Mount Fox NE facing slope at 10,300'. HS 180cm. ECTP2 40cm down on Buried Surface Hoar. ECTP 23 90cm down on MFcr with 1-2mm Facets. Saw several recent wind slab avalanches in steeper windloaded terrrain around Goose Lake, but limited activity was seen on Henderson. Lots of co/cr while touring on Mount Fox. D2 avalanche on east facing Mount Fox that appears to be on the SH layer, triggered by a cornice drop."
Ob1: Photos 1-4, GNFAC
We rode out to Lulu Pass to look at the few avalanches that were reported yesterday on Henderson and Fisher Mtn. Today we did not see any avalanches that weren't previously reported, other than one small, but thick wind slab on south facing slope of Scotch Bonnet (photo). At least the avalanche on Fisher and one on Henderson broke near the ground (pics attached). Some slides were heavily refilled by drifted snow, so it was hard to tell how deep they broke.
Yesterday I saw a wide slab avalanche up on west Woody Ridge from town (photo attached). It happened late on Wednesday or overnight during or after the strong winds and snowfall.
Ob 2: B Fredlund, Photos 5-13
Quite a few natural avalanches observed north of Cooke City today. Photos attached of:
5: NE facing, 10,000, Miller Ridge
6: E facing, 9900', Bull of the Woods Pass
7: NE facing, 9700', Miller Ridge
8: E facing, 10,200' Scotch Bonnet Mtn.
9: E facing, 10,000 Mt. Henderson
10-12: NE- N facing, 10,000' Mt. Henderson
13: NE facing, 10,000' Sheep Creek.
NE facing, 10,000' Sheep Creek.
Photo: B Fredlund
NE- N facing, 10,000' Mt. Henderson
Photo: B Fredlund
NE- N facing, 10,000' Mt. Henderson
Photo: B Fredlund
