Dirty diapers

Location Name: 
Forecaster Observation - Flathead Range
Observation date: 
Friday, March 22, 2019 - 17:30
Is this an Avalanche Observation: 
Yes
Observation made by: Forecaster

Tabs

Quick Observation

Our tour into the Flathead Range was highlighted by impressive wet avalanche carnage 

  • The southerly-facing side of Tunnel Creek was a mess of overlapping wet slabs and wet loose avalanches, ranging from D2 to D4 in size. These appeared to mostly run Thursday and Wednesday. There were only a few paths that hadn’t already flushed to the valley. Northeast aspects at high elevations shed a number of “moist loose” D2 avalanches yesterday and triggered one D2 soft slab. Looking across the Middle Fork at GNP was like looking at a pile of dirty diapers. Lots of slides to the ground.
  • Avalanche activity began today around 11:00 am and continued until we left early afternoon.   We saw mostly just small wet loose slides in our basin. 
  • Limited other views in our travels but the big slides that appeared to run today: D3 wet slab to the ground on a mid elevation southwest aspect across the Middle Fork. A second D3.5 wet loose/ wet slab(?) off of the southwest bowl of Mt. Stanton, started near the summit, viewed from afar.
  • We stuck to our plan to start early and traveled exclusively on due north aspects without overhead hazards feeding in from other aspects. We intentionally triggered a D1.5 wet loose on a relatively small NE facing slope at high elevations, and experienced wet collapses on low angle SW aspects at high elevations. 
Snowpack, Avalanche, Weather Images: 
Snowpack, Avalanche, Weather Videos: 

March 22, 2019. Destructive wet avalanches

Travel Details
Region: 
Flathead Range - Middle Fork Corridor
Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
3500-5000 ft
5000-6500 ft
Above 6500 ft
Aspect(s) of observation: 
N
NE
E
SE
S
SW
W
Red Flags: 
Rapid or prolonged warming
Rollerballs / pinwheels
Persistent Weak Layers: 
Facets or Faceted Crust
On the surface
More comments about the snowpack and weather: 
Light winds might have kept surfaces a little cooler today. Low elevation slopes look pretty worked over now, runneled, brown patches, etc...biggest hazard down low is hits from above. Dry faceted powder still holding strong on due north.
Wind Speed: 
Light (Twigs in motion)
Air temperature: 
Above Freezing
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Thursday, March 21, 2019 - 14:30
Avalanche Type: 
Wet Slab
Failure Plane/Weak Layer: 
Old snow
More information or comments about the avalanche: 

Viewed from debris pile at valley bottom. Start zone mostly obscured by terrain.  Could make out a ~3' crown at about 6000', probably triggered by a wet loose from higher up.  Snapped mature trees. Towers of wet debris 20' tall. 

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
Southeast
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D4 - Could destroy a rail car, large truck, buildings, or swaths of forest
Relative Size: 
R4 Large
Crown Height: 
3 ft
Avalanche Length (Vertical Run): 
2800ft.
Avalanche Location: 
Date and Time of Avalanche: 
Thursday, March 21, 2019 - 15:00
Avalanche Type: 
Unknown
Failure Plane/Weak Layer: 
Old snow
More information or comments about the avalanche: 

Could not see start zone.  Either a wet loose or wet slab from N/ATL.  Debris pile was a day or two old. 

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
Southeast
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D3.5
Relative Size: 
R3 Medium
Avalanche Length (Vertical Run): 
2700ft.
Avalanche Location: 
Date and Time of Avalanche: 
Thursday, March 21, 2019 - 15:00
Avalanche Type: 
Wet Slab
Failure Plane/Weak Layer: 
Old snow
More information or comments about the avalanche: 

Mix of WL and WS in start zone, breaking on 2/2 crust or down to ground.  

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
South
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D3 - Could destroy a car, a wood house, or snap trees
Relative Size: 
R3 Medium
Crown Height: 
3 ft
Avalanche Length (Vertical Run): 
2400ft.
Avalanche Location: 
Date and Time of Avalanche: 
Thursday, March 21, 2019 - 15:00
Avalanche Type: 
Wet Slab
Failure Plane/Weak Layer: 
Old snow
Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
South
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small
Crown Height: 
3 ft
Avalanche Length (Vertical Run): 
500ft.
Avalanche Location: 
Date and Time of Avalanche: 
Thursday, March 21, 2019 - 11:00
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Within storm snow
More information or comments about the avalanche: 

Moist loose on E/NE aspects. One triggered a 1' soft dryish slab. 

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
East
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small
Crown Height: 
Less than 1 ft
Avalanche Location: 
Date and Time of Avalanche: 
Friday, March 15, 2019 - 13:15
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Within storm snow
Hide Trigger
Trigger: 
skier
Hide Terrain
Aspect: 
East
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D1.5
Relative Size: 
R1 Very Small
Crown Height: 
Less than 1 ft
Avalanche Location: 
Date and Time of Avalanche: 
Thursday, March 21, 2019 - 13:15
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Ground
More information or comments about the avalanche: 

Various slides to the ground in Glacier Park on sunny aspects, mostly starting around 6-6.5k',  running full track. Viewed from afar.

Hide Trigger
Trigger: 
natural
Hide Size
Destructive Size: 
D3 - Could destroy a car, a wood house, or snap trees
Relative Size: 
R3 Medium
Avalanche Location: 
Date and Time of Avalanche: 
Friday, March 22, 2019 - 15:15
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Ground
More information or comments about the avalanche: 

New slide off of Stanton, either ran today or yesterday late afternoon.  Looks like it probably started as a WL and pulled in some WS.

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
Southwest
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D3.5
Relative Size: 
R3 Medium
Avalanche Length (Vertical Run): 
3400ft.
Avalanche Location: 
Date and Time of Avalanche: 
Friday, March 22, 2019 - 15:15
Avalanche Type: 
Wet Slab
Failure Plane/Weak Layer: 
Old snow
More information or comments about the avalanche: 

Estimated from afar. Crown and debris looked fresh.  

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
West
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D3 - Could destroy a car, a wood house, or snap trees
Relative Size: 
R4 Large
Crown Height: 
4 ft
Avalanche Location: 
Date and Time of Avalanche: 
Friday, March 22, 2019 - 15:00
Avalanche Type: 
Wet Slab
Failure Plane/Weak Layer: 
Ground
More information or comments about the avalanche: 

Acros the Middle Fork River

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
West
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D3 - Could destroy a car, a wood house, or snap trees
Relative Size: 
R3 Medium
Date and Time of Avalanche: 
Thursday, March 21, 2019 - 17:00
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Ground
More information or comments about the avalanche: 
Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
South
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D3 - Could destroy a car, a wood house, or snap trees
Relative Size: 
R3 Medium
Date and Time of Avalanche: 
Thursday, March 21, 2019 - 14:00
Avalanche Type: 
Wet Loose
More information or comments about the avalanche: 
Hide Trigger
Trigger: 
natural
Hide Terrain
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small