Black n white on Brown

Location Name: 
Forecaster Observation - Mt. Brown
Observation date: 
Monday, February 18, 2019 - 20:45
Is this an Avalanche Observation: 
Yes
Observation made by: Forecaster

Tabs

Quick Observation

To fire lookout on Mt. Brown to look for wind slabs and survey McDonald Creek peaks for recent natural avalanche cycle(s).

  • Snow surface cohesionless, low-density snow from recent storms with little evidence of near-surface slabs. No shooting cracks or collapses.
  • Snow still in trees except in valley floor, indicating winds were not strong enough to transport snow during arctic intrusion.
  • Crowns  from natural avalanches on most steep slopes in the bowl east of the lookout. Similar slides on Mt. Edwards, Stanton peak, but shallow crowns hard to ID from a distance.
  • Look to have been at least two cycles during the past week - soft slabs during the storm, (east, south, and west aspects), wind slabs during arctic intrusion (west slopes).
  • One slide may have failed on deeper layers (soutwest aspect, 6800 ft).
  • One slide notably more recent than others (southwest aspect, 6500 ft).
  • Given the dearth of slabs and signs of instability, we felt comforatble skiing short, consequential pitches 35-40 degrees.

Ski in the white. Don't hit the black. Doesn't get simpler than that.

Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Glacier National Park - McDonald Lake Area
Activity: 
Skiing
Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
3500-5000 ft
5000-6500 ft
Above 6500 ft
Aspect(s) of observation: 
E
SE
S
SW
Persistent Weak Layers: 
Not observed
New Snow in the past 24 hours: 
0.00in.
More comments about the snowpack and weather: 
Calm and cold, with few to scattered clouds. Sun felt great, but did not affect snow surface or cause trees to shed recent snow. Purposely did not dig, in order to keep moving in cold.
Blowing Snow: 
None
Wind Speed: 
Calm (No air motion)
Air temperature: 
Below Freezing
Sky Cover: 
Partly Cloudy (SCT)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Tuesday, February 12, 2019 - 20:45
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
Unknown
More information or comments about the avalanche: 

Multiple slides in bowl east of lookout, generally top of steep aprons below rockbands. No chunky debris. Multiple aspects - E, SE, S, W. All but 1 broke during the storm; only 1 looked like it may have broken deeper, on older snow, but not sure. A few were more like D1.5.

Hide Trigger
Trigger: 
natural
Hide Terrain
Start Zone Slope Angle: 
38
Aspect: 
South
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small
Crown Height: 
2 ft
Avalanche Length (Vertical Run): 
200ft.
Avalanche Width (Average width): 
100ft.
Avalanche Location: 
Date and Time of Avalanche: 
Sunday, February 17, 2019 - 21:15
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
Unknown
More information or comments about the avalanche: 

Clearly fresh. Saturday? Sunday? Solar-induced? 

Hide Trigger
Trigger: 
natural
Hide Terrain
Start Zone Slope Angle: 
36
Aspect: 
Southwest
Starting Elevation: 
6450
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small
Crown Height: 
1 ft
Avalanche Length (Vertical Run): 
200ft.
Avalanche Width (Average width): 
125ft.
Avalanche Location: