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Missoula Avalanche

Public Observation

Observation Details

Observation Date:
April 6, 2022
Submitted:
April 6, 2022
Zone or Region:
Activity:
Skiing/Snowboarding
Location:
Lost horse

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Soft Slab
Size:
Size 3: Could bury and destroy a car, damage a truck, destroy a wood frame house, or break a few trees
Elevation:
7,800
Aspect:
NE
Comments:
Glimpsed this from a distance, maybe 150 yd long crown that was 2-4 ft deep. In a windloaded area maybe 100 yds down from a ridgeline with a 10ft tall new cornice on it. Largest recent avalanche we saw today, slid between 12:30 and 3pm.
Photo:

Signs of Unstable Snow

None reported

Observations

Rode up 10 miles towards the head of the drainage and poked around on mellow slopes. Significant winds started from the SW and shifted to the west, transporting snow 200+yds below ridges. Observed the avalanche above, as well as the smaller ones that slide on NE aspects around 6,500 ft previously. Talked to some riders at the end of the day who saw 4 separate crowns in other bowls near the ridges. Also saw some recent cornice fall on S slopes above the major slide paths on our way out.

On our skin up, no shooting cracks were observed and none of the new, dense snow slid around on side hills. It took multiple jumps on switch backs to get them to shift. New snow wasn't consolidated enough to slab where we skinned and skied.

3 new inches around 5,000 ft, 8 new inches at 5,800 ft, and 18 new inches at 6,000 ft. Temps reached 40° at 6,000 ft and steep, sun affected areas began to rollerball around 11:30. On E slopes around 6,500 ft new snow was saturated 3 inches deep at 3 pm and 8 inches deep on SE slopes at 3pm.

Pit results showed around 250 cm of snow, with ECTN 9 30 cm down on snow interface between warmer new snow and the colder, drier new snow. ECTN 11 15 cm down, and ECTN 15 45 cm down on a below a small melt freeze crust 1 inch on facets above the consolidated, dense, old snow surface.

Media

Small D1-2 avalanches that occurred prior to today, NE slope 6,500 ft.
Rollerballs on N-E aspects 40°+
Pit ECT results

Advanced Observations

Observed Avalanche Problem #1: 

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