Wet carnage in Flathead Range

Location Name: 
Forecaster Observation - Flathead Range
Observation date: 
Friday, April 12, 2019 - 13:30

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

Location

Tabs

Quick Observation

In the Flathead Range, we found stable conditions this morning with wet loose instabilities quickly developing by noon. There were plenty of recent destructive wet avalanches to gawk at and make it an easy decision to retreat from steep terrain once surface crusts broke down.  

  • At low to mid elevations, we found 2" surface refreeze over saturated wet grains.  At mid to upper elevations, we found a soft 1" surface crust (on all but steep north) capping ~8" of recent moist to dry snow.  These crusts effectively put a lid on any surface instabilities this morning.  Surface crusts quickly broke down mid-day during a brief solar / greenhousing period.   We starting ski cutting rollerballs and saw one natural wet loose avalanche from sunlit, rocky terrain (@ 12:15 p.m.)
  • We observed over a dozen wet loose avalanches that ran in the past few days or week on all aspects.  These were mostly D1.5-D2 in size, with a few D3s.  A couple appeared to step down to wet slabs.  Most started at mid-elevations and ran to low elevations.
  • The only dry snow untouched by surface warming was on high, steep north.  The lack of any recent dry slab avalanches along with a lack of results from hand pits, test slopes, and ski cuts suggest that storm slab issues are healing up.   
Snowpack, Avalanche, Weather Images: 
Snowpack, Avalanche, Weather Videos: 

April 12, 2019. Managing the wet loose dragon

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
Red Flags: 
Rapid or prolonged warming
Rollerballs / pinwheels
New Snow in the past 24 hours: 
0.50in.
More comments about the snowpack and weather: 
Overcast/obscured with very light snowfall this morning gave way to partial clearing mid-day, then bouts of light rain. This morning, we found a surface crust to 7,300' on SE aspects. It was also present to at least 6,400' on NE aspects. On due North, the snow was dry still. Seems like it was some kind of greenhouse warming yesterday afternoon.
Blowing Snow: 
None
Wind Speed: 
Calm (No air motion)
Air temperature: 
Above Freezing
Snow line: 
6000'
Sky Cover: 
Mostly Cloudy (BRK)
Highest Precipitation Rate: 
Very Light Snowfall (S-1)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Friday, April 12, 2019 - 12:15
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Within storm snow
Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
Northeast
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D1.5
Relative Size: 
R1 Very Small
Avalanche Location: 
Date and Time of Avalanche: 
Thursday, April 11, 2019 - 14:45
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Within storm snow
More information or comments about the avalanche: 

Various aspects in Rescue and Skiumah

Hide Trigger
Trigger: 
natural
Hide Terrain
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small
Avalanche Location: 
Date and Time of Avalanche: 
Wednesday, April 10, 2019 - 13:00
Avalanche Type: 
Wet Loose
More information or comments about the avalanche: 

May have started as a dry loose at upper elevations and ran into wet snow down lower. May have triggered a couple of smaller wet slabs as well.  Failure date is best guess.

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
Northeast
Starting Elevation: 
near-treeline
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: 
Wednesday, April 10, 2019 - 12:00
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Within storm snow
Hide Trigger
Trigger: 
natural
Hide Terrain
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small
Avalanche Location: 
Date and Time of Avalanche: 
Wednesday, March 20, 2019 - 10:30
Avalanche Type: 
Hard Slab
Failure Plane/Weak Layer: 
Old snow
Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
Northeast
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D3 - Could destroy a car, a wood house, or snap trees
Crown Height: 
4 ft
Avalanche Location: 
Date and Time of Avalanche: 
Tuesday, April 9, 2019 - 13:00
Avalanche Type: 
Wet Loose
More information or comments about the avalanche: 
Hide Trigger
Trigger: 
natural
Hide Terrain
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small