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Soft Slab & Sluff
Location Name:
Lake McDonald Area
Observation date:
Wednesday, February 16, 2022 - 15:15
Is this an Avalanche Observation:
Yes
Observation made by:
Public
Location
Tabs
Quick Observation
Toured in the Lake McDonald area to enjoy new snow, clear weather and make observations.
Skier triggered a D1 Soft Slab avalanche while descending a >40° slope on a SE aspect.
Observed several small loose dry sluff debris from overnight or earlier in the day.
Was able to ski off to the flank of the small slab. Runout was wide and shallow but a good reminder of choosing inconsequential terrain.
Observed ~12" new snow at upper elevations sitting on a firm crust on all southerly aspects.
Calm conditions throughout the day with several hours of bluebird followed by partly sunny conditions.
Snowpack, Avalanche, Weather Images:
Travel Details
Region:
Glacier National Park - McDonald Lake Area
Activity:
Skiing
Snowpack Details
Snowpack and Weather Details:
Terrain
Elevation of observation:
3500-5000 ft
5000-6500 ft
Above 6500 ft
Aspect(s) of observation:
SE
S
SW
W
Red Flags:
Avalanches from the past 2 days
Persistent Weak Layers:
Not observed
New Snow in the past 24 hours:
12.00in.
More comments about the snowpack and weather:
Increasing snow accumulation amounts with each elevation band, with approximately 12" new snow at upper elevations. Some evidence of overnight easterly winds.
Blowing Snow:
Previous
Wind Speed:
Calm (No air motion)
Air temperature:
Below Freezing
Sky Cover:
Partly Cloudy (SCT)
Highest Precipitation Rate:
No Precipitation (NO)
Avalanche Details
Avalanche Details:
Number of avalanches:
4
Avalanche Type:
Soft Slab
Failure Plane/Weak Layer:
New/old snow interface
Trigger
Trigger:
skier
Trigger Modifier:
Accidentally Triggered
Terrain
Start Zone Slope Angle:
40
Aspect:
Southeast
Starting Elevation:
above-treeline
Size
Destructive Size:
D1 Relatively harmless to people.
Relative Size:
R2 Small
Crown Height:
1 ft
Avalanche Length (Vertical Run):
200ft.
Avalanche Width (Average width):
50ft.
People Involved
Number of people caught:
0
Number of partial burials:
0
Number of full burials:
0
Avalanche Location:
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