From IG #gnfacobs post: "An avalanche from early Tuesday (02/18) morning caused by a natural cornice fall. Note the step down partway down the path. ENE @ 9700. Ran 1300’." Photo: A. Whitmore
We saw this crown on an east aspect around 9,000 feet above Blackmore lake on 2/21/20. It likely broke during the weekend of 2/15-2/16, but could be more recent. Photo: GNFAC
Crown of an avalanche that broke the weekend of 2/14-2/15 on a SE aspect around 9,700' on Mt. Blackmore in Hyalite. Depth was 3-5 feet. Avalanche in background is one of at least seven we saw in this drainage. Photo taken 2/21/20: GNFAC
Crown of an avalanche that broke the weekend of 2/14-2/15 on a SE aspect around 9,700' on Mt. Blackmore in Hyalite. Depth was 3-5 feet. Photo taken 2/21/20: GNFAC
Debris from an avalanche that broke the weekend of 2/14-2/15 on the north face of Mt. Blackmore in Hyalite. Photo taken 2/21/20: GNFAC
Skiers saw these deep slabs in Maid of the Mist in Hyalite on 2/21/20. Doug Chabot went to the site on the 2/22.
The avalanches were big and deep. They ran on the facets/depth hoar near the ground. The slide (1&2) ran to their maximum runout.
Aspect: South to East
Elevation: 9900'
Slope Angle: estimated 45+ degrees at the steepest with average of 40 degrees.
Using Google Earth
Crown: 9930'
Toe of Debris: 9316' with a measured Alpha Angle of 16 degrees
Using picture "4 avalanches..." as reference:
From email on 2/21/20: "...observed today from the highway. It appears like it was probably triggered by a skier yesterday (on Feb. 20). It was on a south aspect around 8,000', and estimated to be 1-2' deep and about 30' wide.
Additionally, there were a couple of wet, point release avalanches that ran today on other southerly aspects, due to abundant sunshine and warming temps. Aside from that, no other slab avalanche activity nor signs of instability observed this last week around Cooke City."
From email on 2/21/20: "...observed today from the highway. It appears like it was probably triggered by a skier yesterday (on Feb. 20). It was on a south aspect around 8,000', and estimated to be 1-2' deep and about 30' wide." Photo: B. Fredlund
Natural avalanche in the Maid of the Mist Cirque. Photo taken 2/21/2020. Avalanche appears to have broken earlier in the week.
Photo: R. Phipps
