Big Deep Slabs in Maid of the Mist, Hyalite

Maid of the Mist
Northern Gallatin
Code
HS-N-R4-D3.5-O
Elevation
9900
Aspect
SE
Aspect Range
E-S
Latitude
45.41640
Longitude
-110.97000
Notes

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

  • Latitude:  45°24'49.65"N
  • Longitude: 110°58'49.04"W

Using picture "4 avalanches..." as reference:

  1. was 300' wide, 6-8 feet deep
  2. 1300' wide; it ran from east to south aspect; was 10-12 feet deep; ran 2150' slope distance,
  3. was 150' wide, 450' slope distance, 4-5 feet deep
  4. was 250' wide and had a measured Alpha Angle of 26 degrees, 4-5 feet deep and ran 775 slope distance.
Number of slides
4
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
4
D size
3.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
120.0 inches
Vertical Fall
600ft
Slab Width
1300.00ft
Weak Layer Grain type
Depth Hoar
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year