They Raised the Price of Admission

Location Name: 
Forecaster Observation - Flathead Range
Observation date: 
Friday, March 19, 2021 - 16:45

Is this an Avalanche Observation: 
Yes
Observation made by: Forecaster

Tabs

Quick Observation

For some reason we didn't see anyone else when we went to look for today's avalanche problems in the Middle Fork.

  • We saw glide cracks galore. We saw them in places we expected - on steep southeast facing slopes at middle elevations. We saw them places we didn't expect - on northeast-facing slopes near and above treeline. 
  • The snowpack below 5,000 feet has been through several melt-freeze cycles with stout crusts or enough drainage established that water is passing through the snowpack to the ground. Rain overnight had saturated the whole snowpack up to that elevation, and we sunk through, but couldn't trigger so much as a roller ball.
  • Once we hit the middle elevation band (5,000-6,500 ft) we found cohesionless wet snow to the ground with only the faintest hint of crust on south and west aspect. The snowpack is thinner there from seasonal stripping by prevailing winds. It was the kind of snow deep wet loose avalanches are made of.
  • At those same elevations, but on north and east aspects, we found 4-6 inches of dry snow becoming wet for the first time. We easily triggered large roller balls and a small wet loose avalanche. 
  • We dug a snow pit to look at old persistent weak layers on a northeast aspect at 5,800 feet where they were only buried about 28 inches deep. We couldn't get them to propagate in extended column or propagation saw tests. Interestingly, we found buried surface hoar in one end of our pit, but not at the other.

The "skiing" on the way down was knee-wrenchingly dreadful. I wouldn't do it for fun.

Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Flathead Range - Middle Fork Corridor
Route Description: 

To 5800 ft

Activity: 
Skiing
Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
3500-5000 ft
5000-6500 ft
Aspect(s) of observation: 
N
NE
E
SE
S
SW
W
NW
Red Flags: 
Avalanches from the past 2 days
Rapid or prolonged warming
Rollerballs / pinwheels
Persistent Weak Layers: 
Surface Hoar
Facets or Faceted Crust
Buried
New Snow in the past 24 hours: 
1.00in.
Total Snow Depth: 
170cm
More comments about the snowpack and weather: 
Snow line overnight was 7000ft and dropped to 5000ft when showers started this morning. We did not travel through any elevations that had frozen overnight. Rain on the canyon floor all day. The snowpack on north and east aspects was wet for the top 5cm, moist for the next 20cm and dry below that. We were bombed by a natural roller ball in our snow pit while digging - NE aspect NTL.
Blowing Snow: 
None
Wind Speed: 
Light (Twigs in motion)
Wind Direction: 
West
Air temperature: 
Above Freezing
Snow line: 
5000 ft
Sky Cover: 
Mostly Cloudy (BRK)
Highest Precipitation Rate: 
Very Light Snowfall (S-1)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Friday, March 19, 2021 - 13:30
Number of avalanches: 
1
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Old snow
More information or comments about the avalanche: 
Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Intentionally Triggered
Hide Terrain
Start Zone Slope Angle: 
40
Aspect: 
Northeast
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R1 Very Small
Crown Height: 
Less than 1 ft
Avalanche Length (Vertical Run): 
200ft.
Avalanche Width (Average width): 
30ft.
Avalanche Location: