More debris from last week's warming

Location Name: Flathead Range Observation date: Tuesday, April 14, 2020 - 16:15	Is this an Avalanche Observation: Yes

Observation made by: Public

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Quick Observation

We went for a gentle tour to enjoy low-angle corn snow and observe avalanche activity related to last week's warming.

Balmy temperatures April 8-10 put the hurt on southeasterly slopes resulting in 1 D3, 1 D2.5, 3 D2, and a dozen D1.5 wet loose slides. One of these appears to have initiated a wet slab avalanche on an east aspect at approximately 5000'.
A slab avalanche was observed on an east aspect at 7200'. It appears to have been started by a point release sluff.
Northerly slopes fared slightly better with 10 D1-1.5 slides and numerous rollerballs.
Several days of cold temperatures left a supportable snow surface at low and mid-elevations. Today's corn window appeared to be relatively long with just the top few inches softened by 2:00 p.m at low and mid-elevations.

Snowpack, Avalanche, Weather Images:

Travel Details

Region:

Flathead Range - Middle Fork Corridor

Activity:

Skiing

Snowpack Details

Snowpack and Weather Details:

Terrain

Elevation of observation:

3500-5000 ft

5000-6500 ft

Aspect(s) of observation:

Persistent Weak Layers:

Not observed

New Snow in the past 24 hours:

0.00in.

Wind Speed:

Light (Twigs in motion)

Wind Direction:

West

Air temperature:

Above Freezing

Snow line:

3000'

Sky Cover:

Mostly Clear (FEW)

Avalanche Details

Avalanche Details:

Date and Time of Avalanche:

Thursday, April 9, 2020 - 12:15

Number of avalanches:

Avalanche Type:

Wet Loose

Failure Plane/Weak Layer:

Within storm snow

More information or comments about the avalanche:

Several large wet loose slides merged in a gulley depositing a D3 debris pile.

Trigger

Trigger:

natural

Terrain

Start Zone Slope Angle:

Aspect:

Southeast

Starting Elevation:

near-treeline

Size

Destructive Size:

D3 - Could destroy a car, a wood house, or snap trees

Relative Size:

R3 Medium

Avalanche Length (Vertical Run):

1600ft.

Avalanche Width (Average width):

400ft.

Avalanche Location:

Date and Time of Avalanche:

Thursday, April 9, 2020 - 12:15

Number of avalanches:

Avalanche Type:

Wet Loose

Failure Plane/Weak Layer:

Within storm snow

More information or comments about the avalanche:

Trigger

Trigger:

natural

Terrain

Start Zone Slope Angle:

Aspect:

Southeast

Starting Elevation:

near-treeline

Size

Destructive Size:

D2 Could bury, injure, or kill a person.

Relative Size:

R2 Small

Avalanche Length (Vertical Run):

1500ft.

Avalanche Width (Average width):

100ft.

Avalanche Location:

Date and Time of Avalanche:

Thursday, April 9, 2020 - 12:15

Number of avalanches:

Avalanche Type:

Wet Loose

Failure Plane/Weak Layer:

Within storm snow

More information or comments about the avalanche:

Trigger

Trigger:

natural

Terrain

Start Zone Slope Angle:

Aspect:

Southeast

Starting Elevation:

near-treeline

Size

Destructive Size:

D2 Could bury, injure, or kill a person.

Relative Size:

R2 Small

Avalanche Length (Vertical Run):

1000ft.

Avalanche Width (Average width):

75ft.

Avalanche Location:

Date and Time of Avalanche:

Thursday, April 9, 2020 - 12:15

Avalanche Type:

Wet Loose

Failure Plane/Weak Layer:

Within storm snow

More information or comments about the avalanche:

Trigger

Trigger:

natural

Terrain

Start Zone Slope Angle:

Aspect:

Southeast

Starting Elevation:

near-treeline

Size

Destructive Size:

D1.5

Relative Size:

R2 Small

Avalanche Length (Vertical Run):

400ft.

Avalanche Width (Average width):

50ft.

Avalanche Location:

Date and Time of Avalanche:

Thursday, April 9, 2020 - 12:15

Number of avalanches:

Avalanche Type:

Soft Slab

Failure Plane/Weak Layer:

Other - explain below

More information or comments about the avalanche:

This may be a persistent slab that failed on the 3/24 weak layer.

Trigger

Trigger:

natural

Terrain

Start Zone Slope Angle:

Aspect:

East

Starting Elevation:

7200'

Size

Destructive Size:

D2 Could bury, injure, or kill a person.

Relative Size:

R2 Small

Crown Height:

2 ft

Avalanche Length (Vertical Run):

1200ft.

Avalanche Width (Average width):

100ft.

Avalanche Location:

Date and Time of Avalanche:

Thursday, April 9, 2020 - 12:30

Number of avalanches:

Avalanche Type:

Loose Dry/ Sluff

Failure Plane/Weak Layer:

Within storm snow

More information or comments about the avalanche:

On NE-NW aspects.

Trigger

Trigger:

natural

Terrain

Start Zone Slope Angle:

Aspect:

Northwest

Starting Elevation:

near-treeline

Size

Destructive Size:

D1.5

Relative Size:

R1 Very Small

Avalanche Length (Vertical Run):

200ft.

Avalanche Width (Average width):

30ft.

Avalanche Location:

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