Very Large avalanche on Henderson Mtn.

Henderson Mountain
Cooke City
Code
HS-N-R3-D3-O
Elevation
10200
Aspect
NE
Latitude
45.05360
Longitude
-109.94600
Notes

On 3/1/23 at 11am we saw a very large avalanche crown on the east side on Henderson Mtn., in the big avalanche path off the highest summit. It likely occurred late yesterday or early this morning. There was minimal new or drifted snow covering it, and it was snowing and blowing yesterday all day.

I estimate the crown is 6-8 feet deep, possibly 10 feet in spots. Measured on GoogleEarth to be 700 feet wide. 1200 feet vertical. HS-N-R3-D3-O. It did not go to the ground. Given how much wind-loading this path gets it may have been near the interface the 6 feet of snow that fell over the last 7-10 days, but it easily could have broken on a variety of faceted layers deeper in the snowpack.

Today wind was very calm and skies were partly cloudy. We saw a few shots of blue sky mixed with a few snow showers that totaled maybe 2-3cm.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
3
D size
3
Bed Surface
O - Old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
84.0 inches
Vertical Fall
1200ft
Slab Width
700.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year