Silver Tongued Devil

Location Name: 
Forecaster Observation - JF Stevens Canyon
Observation date: 
Sunday, March 29, 2020 - 20:00

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

Location

Tabs

Quick Observation

Day off tour to JF Stevens Canyon to look for dry-ish snow. We found:

  • Wet snow, even on northerly aspects, to about 5000 feet. This goo was up to 10" deep in places. On our descent, we triggered several wet loose slides that quickly gained mass, though they intially ran about 3" deep (Avalanche details tab ). On bigger slopes with long, steep pitches, these could pose a serious hazard. 
  • About 3" of fresh snow that was moist snow to nearly 6500 feet. Because of rain and warming, it's hard to tell how much snow has fallen in this area in recent days. Maybe 5-7".
  • We found slopes between about 5000 and 5800 feet were littered with natural rollerballs. Guessing these occurred with rain overnight and this morning. 
  • Above about 6500 feet, the snow was dry and prone to drifting by moderate southwesterly winds. West-facing slopes were alternately scoured to a recent crust or slathered with small, soft drifts up to a foot thick. We saw some short cracks in these drifts but were unable to release any slabs on slopes below 35*. 
  • At upper elevation ridges, the winds were blowing snow off cornices most of the day. While there wasn't a lot of snow to transport, this drifting snow was forming soft slabs on the lee sides of ridges and below cornices. The one we tested directly below a ridge at 6700 feet did not crack.

We stuck to moderately angled, planar slopes where any drifts were patchy. We didn't venture into the most wind loaded terrain. 

Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Flathead Range/Glacier National Park - John F. Stevens Canyon
Route Description: 

to 7700'

Activity: 
Skiing
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
SW
W
NW
Red Flags: 
Avalanches from the past 2 days
Rain on snow
Rapid or prolonged warming
Rollerballs / pinwheels
New Snow in the past 24 hours: 
2.00in.
More comments about the snowpack and weather: 
Rain showers (RV-RL) ended late morning. A few snow showers up high. Rain (RV->RL-RM) in middle fork from Essex to West Glacier, heaviest in Nyack area. With snow moist through mid elevations, and scouring/ drifting up high, hard to tell how much snow fell in the past day or so.
Blowing Snow: 
Moderate
Wind Speed: 
Moderate (Small trees sway)
Wind Direction: 
Southwest
Air temperature: 
Above Freezing
Snow line: 
6000
Sky Cover: 
Mostly Cloudy (BRK)
Highest Precipitation Rate: 
Moderate Rain (RM)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Sunday, March 29, 2020 - 15:00
Number of avalanches: 
4
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
New/old snow interface
More information or comments about the avalanche: 

Although rollerballs released from ski turns from about 6000 feet down on northerly slopes, below about 5000 feet the wet snow released from ski turns became more substantial and consequential. We were in/ adjacent to a steep, northerly gully, so the debris didn't have far to run. Guessing these could have grown to D2 had they occurred on a steep slope with a long continuous pitch. 

Hide Trigger
Trigger: 
skier
Hide Terrain
Start Zone Slope Angle: 
40
Aspect: 
North
Starting Elevation: 
below-treeline
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R2 Small
Crown Height: 
Less than 1 ft
Avalanche Length (Vertical Run): 
30ft.
Avalanche Width (Average width): 
6ft.
Avalanche Location: 
Date and Time of Avalanche: 
Sunday, March 29, 2020 - 13:15
Number of avalanches: 
1
Avalanche Type: 
Glide
Failure Plane/Weak Layer: 
Ground
More information or comments about the avalanche: 

Partial release of glide crack above Shed 12. Ran to bench above shed. More cracks on the slope. 

Hide Trigger
Trigger: 
natural
Hide Terrain
Start Zone Slope Angle: 
44
Aspect: 
East
Starting Elevation: 
4300
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R2 Small
Crown Height: 
2 ft
Avalanche Length (Vertical Run): 
200ft.
Avalanche Width (Average width): 
12ft.
Avalanche Location: 
Date and Time of Avalanche: 
Sunday, March 29, 2020 - 14:00
Number of avalanches: 
1
Avalanche Type: 
Wet Loose
Failure Plane/Weak Layer: 
Unknown
More information or comments about the avalanche: 

TIme is a guess based on elevation of start zone and aspect. Debris down to creek bottom at about 5000'.

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
Avalanche Length (Vertical Run): 
1200ft.
Avalanche Location: