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Arctic Arrival
Location Name:
BNSF Avalanche Program-Snowslip Mtn. GNP
Observation date:
Friday, February 8, 2019 - 21:45
Is this an Avalanche Observation:
No
Observation made by:
Public
Tabs
Quick Observation
Toured up the Infinity/Shed 9 ridge on the south face of Snowslip Mtn. and traversed over to the top of the Shed 7 W path. Descended Shed 7 W back to the Hwy.
Objective was to investigate the avalanche that ran in the Infinity path last Tuesday (2/5). The crown was mostly filled back in with new snow and we could not safely reach the location of the avalanche. But dug a pit and profile about 50 yards east of the site.
Also wanted assess the most recent wind loading.
The Arctic front arrived a bit earlier than expected. By late morning temperatures were dropping and winds had clocked from the W to the NE and were increasing in speed.
Very light snowfall most of the day with overcast skies in the AM and broken skies by early afternoon.
Moderate NE winds were lightly loading westerly aspects at all elevations.
Only about 1-2 inches of new snow in the past 24 hours.
The NE winds were forming thin new slabs primarily on S-SW-W aspects at all elevations today.
These new slabs were actually more reactive at low-mid elevations. Ski cut one very small slab, 6” thick x 12’ wide at about 5000 feet.
We dug a snowpit and conducted a full snow profile on a south aspect at 6200 feet elevation on the ridge immediately to the east of the Infinity path.
Still not certain what the weak layer/failure plane was for the Feb 5 Infinity avalanche. But we suspect a layer of surface hoar that formed in mid-January and was buried about 2 feet below the surface at the pit location.
Cornices in Infinity, Shed 9, and Shed 7 were eroding back into the slope by the wind.
No avalanche activity observed since Tuesday February 5th.
Snowpack, Avalanche, Weather Images:
Avalanche Details
Avalanche Details:
Date and Time of Avalanche:
Friday, February 8, 2019 - 21:45
Avalanche Type:
Soft Slab
Failure Plane/Weak Layer:
New/old snow interface
More information or comments about the avalanche:
The NE winds were forming thin new slabs primarily on S-SW-W aspects at all elevations today.
These new slabs were actually more reactive at low-mid elevations. Ski cut one very small slab, 6” thick x 12’ wide at about 5000 feet.
Trigger
Trigger:
skier
Trigger Modifier:
Intentionally Triggered
Terrain
Aspect:
South
Starting Elevation:
5000
Size
Destructive Size:
D1 Relatively harmless to people.
Relative Size:
R1 Very Small
Crown Height:
Less than 1 ft
Avalanche Width (Average width):
12ft.
Avalanche Location:
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