Long running sluff near Avalanche Lake
Location Name: Forecaster Observation - Little Matterhorn, Glacier National Park Observation date: Thursday, December 14, 2017 - 15:15 |
Is this an Avalanche Observation: Yes |
---|
Observation made by: Forecaster
Location
Tabs
Avalanche Details:
Date and Time of Avalanche:
Thursday, December 14, 2017 - 13:15
Avalanche Type:
Loose Dry/ Sluff
Failure Plane/Weak Layer:
New/old snow interface
Trigger:
skier
Trigger Modifier:
Intentionally Triggered
Start Zone Slope Angle:
45
Aspect:
Northeast
Starting Elevation:
7000
Destructive Size:
D2 Could bury, injure, or kill a person.
Relative Size:
R1 Very Small
Crown Height:
Less than 1 ft
Avalanche Length (Vertical Run):
2000ft.
Avalanche Width (Average width):
40ft.
Number of people caught:
0
Avalanche Location:
Started shallow but quickly gathered all of the snow above the Thanksgiving crust. It ran at least 2,000 vertical feet and entrained enough volume on the way down to be a D2. We did not see exactly how far it ran (I'm guessing 2700 feet) or the toe of the debris pile, but there were piles of debris ~3 feet deep mid track. It also pulled out a couple of thin wind slabs, ~4" thick or so.
Its worth noting that any shallow storm instabilities with this incoming system have potential to entrain all of the snow down to the Thanksgiving crust, compounding the size of avalanches.