Valanga

Central Bitterroots- Ward

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Quick report

Signs of previous wind loading on N/NE aspects, even in terrain as low as 6500'. The observed natural avalanche was caused by wind loading in normally sheltered terrain. Check for wind loading on N/NE aspects, >35 degrees. Stability tests indicate that although the snowpack is right side up, the new snow hasn't completely bonded to the old snow surface. The new snow is low density F/4F and hasn't consolidated into a slab. While the snow stays cold, there is potential for sizeable sluffing in steep terrain. Post storm winds yesterday, above 8000', have slightly impacted the snow surface but no fresh wind slabs were observed. No signs of instability observed today.

Weather

Air Temp
5-18F
Cloud Cover
clear
Wind Loading
previous
Rain Elevation
Not Observed
Recent Snowfall
25CM
Snow Avail For Transport
none

Clear sunny skies until mid-afternoon, when increased cloud cover arrived from the west. Temperatures were cold early 5F (-15C) rising to the upper teens 18F (-8C) by mid-day. Mostly calm winds with only an occasional light breeze from the west <5MPH.

Snowpack

New snow amounts from earlier this week: elevation 4300' = 2" (5CM), 5000' = 4", (10CM) , 6000' = 6-8" (15-20CM), above 7000' = 8-14" (25-35CM). Still minimal coverage below 5000'. New snow below 6000' is sitting on a firm, supportable crust. At 7600' on a NE aspect, the total snow depth was 170cm. Stability tests indicate the 10" (25CM) new snow (F-4F) is still bonding with the old snow surface (1F). CT 13, CT18 @ 25 SP, ECTN 21 @ 25.

Avalanche

Size
D2 R2
Type
SS
Aspect
N
Trigger
N
Elevation
6500 ft

Previous avalanche that occured earlier this week during the storm. Wind loaded slope >40 degrees that failed on the new/old snow interface.