Northern Gallatin

Small new snow avalanches at Bridger

Bridger Bowl
Bridger Range
Code
SS-N-R1-D1.5-I
Elevation
8500
Aspect Range
E-NE
Latitude
45.81560
Longitude
-110.92300
Notes

Thursday, November 21:

1. "I observed 2 natural avalanches on the slopes between the Apron and Ramp. No ski tracks in those areas. I thought I took a picture but didn’t. Looks like they both started in the rock bands below the ridge. One was small and the other was considerably larger. Hard to know if they ran today or yesterday. Looked like it was just new snow. Pretty much east aspect."

2. "Toured up to the ridge at Bridger today and traversed into Bridger Gully. At around 8,000' in the trees above the most prominent snowfield, my partner and I observed very small dry sluffs confined to the new snow. Bellow Bridger Gully, my partner was able to release a slide while traversing through rocks above his intended line. This was on an east-southeast aspect at 7,500'. Snow just a few degrees more to the east was dryer. The snowpack nearby thinned greatly on the east-southeast aspect.

Wednesday, November 20:

1. " Noted some activity (D1-D2) isolated to the new snow around rock features and ridgetops that were wind-affected.  Our pit revealed a weakening and thin snowpack due to the drier weather, however, the facet growth at the ground has remained fairly slow and has maintained moisture."

Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
1
D size
1.5
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

From obs.: "I went skiing at Bridger today,... There was 4-5” of new snow, which was sitting on a firm surface. The wind had done some work, and I was able to break off a few shallow (6”) wind slabs in the first 100 feet or so off the ridge." Photo: A. Schauer

Bridger Range, 2019-11-20

Rivers of loose snow avalanches in Flanders Drainage

Flanders Creek
Northern Gallatin
Code
L-N-I
Elevation
9500
Aspect
E
Latitude
45.44020
Longitude
-110.93100
Notes

From Doug Chabot:

I went ice climbing in Flanders and got hit with a graupel storm (0830) which avalanched off the climbs on east-facing slopes for over an hour. It was pretty spectacular and we found knee deep graupel (small, ball-bearing like grains) 200 vertical feet from the bottom of the cliffs. The climbs that we saw this on were Big Sleep, Bobo Like and Killer Pillar. The snow appears to be sliding on a razor thin ice crust under the 3" of new snow that fell last night, which was dense (estimated 15%).

I dug a hand pit to the ground and found 2' of mostly solid snow (no obvious facets) with a couple ice crusts in the upper third. A CT cut with a ski pole yielded no fractures. Elevation 8,000', east aspect.

Number caught
0
Number buried
0
Avalanche Type
Loose-snow avalanche
Trigger
Natural trigger
Bed Surface
I - Interface between new and old snow
Problem Type
Loose Dry
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

From obs: "Went for a tour up to Hyalite Basin. No recent sightings of avalanche activity in the basin. There was substantial wind effect on East aspects at 9,000 feet including a dense 3 inch wind layer that was present up to the saddle, which did not propagate in our ECT. We observed a crust layer on south aspects at 7,000 which likely formed before the most recent snow." Photo: Tommy Saulnier

Northern Gallatin, 2019-11-16

Small wet avalanche in Beehive

Beehive Basin
Northern Madison
Code
N-R0-D1-G
Elevation
8900
Aspect
SW
Latitude
45.34070
Longitude
-111.39100
Notes

From an email: "I observed a wet loose avalanche that most likely occurred yesterday afternoon. Occurred at an elevation of 8,900' on a WSW aspect, along the runout of a chute sometimes referred to as "the gem". It wasn't very large, but it ripped out to the ground in sections and looked like it could do some damage if caught off guard. I assessed the snowpack next to the small slide, and found a snowpack of only 30 cm composed of facets from 0-14 cm above the ground (F hardness), a crust of large bonded grains from 14-16 cm above the ground, small facets / rounding facets from 16-23 cm above the ground, a rain crust from 23-27 cm that blended into wet snow on the surface becoming slabby in the afternoon sun."

Number of slides
1
Number caught
0
Number buried
0
Trigger
Natural trigger
R size
0
D size
1
Bed Surface
G - Ground
Problem Type
Wet Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year