Doin' the Humpty-Hump

Location Name: Furlong/Devils Hump Observation date: Sunday, March 10, 2019 - 22:45	Is this an Avalanche Observation: Yes

Observation made by: Forecaster

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Quick Observation

Exploring in the Tranquil Basin area.

Triggered one small, thin pocket of drifted snow on an easterly, upper-elevation slope with a ski cut. Did not propagate or run far.
Saw one crown from a natural avalanche below a wildly-cantilevered cornice on a northeasterly, upper-elevation slope. 1-2 days old?
Spatially-variable, bullet-hard slabs near highest ridges and peaks. Present near one summit on northeast and east facing slopes; not present on the next. Westerly sides of ridges scoured on one peak; not the next.
Moderate westerly winds were drifting snow early afternoon, but it was primarily surface hoar and facets, so unlikely to form a slab.
Best quality snow on sheltered, northerly slopes at mid-elevations.

Travel Details

Region:

Flathead Range/Glacier National Park - John F. Stevens Canyon

Route Description:

Furlong/ Devils Hump/ out Bronze Stairs

Activity:

Skiing

Snowpack Details

Snowpack and Weather Details:

Terrain

Elevation of observation:

3500-5000 ft

5000-6500 ft

Above 6500 ft

Aspect(s) of observation:

Red Flags:

Blowing snow

Persistent Weak Layers:

Surface Hoar

Facets or Faceted Crust

On the surface

New Snow in the past 24 hours:

0.00in.

More comments about the snowpack and weather:

-5 at highway in AM; near freezing in PM. Winds picked up during the day, with steady moderate westerly winds by early afternoon at ridges and gusty L-M winds lower. Light to moderate blowing snow, but mostly consisted of large surface hoar or facets (fun to watch) but won't readily form slabs.

Blowing Snow:

Moderate

Wind Speed:

Moderate (Small trees sway)

Air temperature:

Below Freezing

Sky Cover:

Partly Cloudy (SCT)

Highest Precipitation Rate:

No Precipitation (NO)

Avalanche Details

Avalanche Details:

Date and Time of Avalanche:

Sunday, March 10, 2019 - 12:30

Avalanche Type:

Soft Slab

Failure Plane/Weak Layer:

New/old snow interface

More information or comments about the avalanche:

Obvious small drift on steep slope. Triggered w ski cut. Did not propagate or run far. Much more benign than yesterday's triggered slides.

Trigger

Trigger:

skier

Trigger Modifier:

Intentionally Triggered

Terrain

Start Zone Slope Angle:

Aspect:

East

Starting Elevation:

7000

Size

Destructive Size:

D1 Relatively harmless to people.

Relative Size:

R1 Very Small

Crown Height:

Less than 1 ft

Avalanche Length (Vertical Run):

60ft.

Avalanche Width (Average width):

15ft.

People Involved

Number of people caught:

Avalanche Location:

Date and Time of Avalanche:

Sunday, March 10, 2019 - 23:00

Avalanche Type:

Soft Slab

Failure Plane/Weak Layer:

Unknown

More information or comments about the avalanche:

Below a wildly-overhanging cornice. Looked deeper than a foot in places. Looked fresh within the past 1-2 days.

Trigger

Trigger:

natural

Terrain

Aspect:

Northeast

Starting Elevation:

6800

Size

Destructive Size:

D1.5

Relative Size:

R2 Small

Avalanche Length (Vertical Run):

125ft.

Avalanche Width (Average width):

80ft.

People Involved

Number of people caught:

Avalanche Location:

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