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At Least We Missed the Rain
Location Name:
Forecaster Observation - Middle Fork
Observation date:
Friday, April 5, 2019 - 14:30
Is this an Avalanche Observation:
No
Observation made by:
Forecaster
Tabs
Quick Observation
We traveled on north-facing terrain to monitor wet snow conditions.
We found 2 to 4 inches of recent snow above 6000'. It was getting moist and causing small natural rollerballs from 6500' up to our high point around 7300'. This new snow was poorly bonded to a thin melt-freeze crust with dry facets underneath of that. There were large cornices with some obvious, small wind deposits just below the summit ridge. We stopped a few hundred feet short of there to avoid the overhead hazard.
The snow was wetter and more reactive below 6500'. We managed to trigger several small wet sluffs (up to D1) between 6500' and 6100' while ski cutting northerly slopes steeper than 45 degrees. We easily triggered large rollers below about 6000' where the snowpack was isothermal, but not sluffs.
A poor refreeze overnight meant that the snow below about 5000' was punchy and wet, even in the morning. It got worse in the afternoon and we had to ski very cautiously.
We skied very steep terrain after testing it with ski cuts. We avoided extreme terrain near rocks and trees that could further warm the wet snowpack. We avoided steep slopes above terrain traps.
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
Above 6500 ft
Aspect(s) of observation:
N
NE
E
Red Flags:
Rapid or prolonged warming
Rollerballs / pinwheels
Persistent Weak Layers:
Facets or Faceted Crust
Buried
New Snow in the past 24 hours:
0.00in.
Total Snow Depth:
160cm
More comments about the snowpack and weather:
The upper snowpack structure above about 5600' is similar to what I have seen elsewhere recently. There is a few inches of newer snow that is getting wet on top of a weak MFcr. Under that crust there is weak snow down about 4" to another crust. The difference now is the snow between the crusts. Whereas last week the this layer was dry faceted snow at middle elevations, it is now MFpc up to about 6000' where I found it was still dry facets. I did 2 quick snowpack tests. @6150, NE aspect: CTM SP down 15cm in the FCs (moist here) on top of the second crust. CTH down 45cm in between 1F hard wind deposits. ECTN in the 15cm FC layer. @7280', E aspect: CTM SP in the same FC layer (dry here, larger and better developed, and down 20cm); the snowpack at this elevation is mostly facets. 2-4" of new snow (from the night of the 3rd) was mostly graupel. It was getting wet up to at least 7300'. Above about 6500' the graupel (4F) sat on top of dry, F hard NSFs which were poorly bonded to the top of a MFcr (down about 6"). A few shots of sunlight. A few spritzers of very light rain/snow mix. Light to moderate rain at the trailhead and on the drive back out.
Blowing Snow:
None
Wind Speed:
Calm (No air motion)
Air temperature:
Above Freezing
Snow line:
7000ft
Sky Cover:
Overcast (OVC)
Highest Precipitation Rate:
Very Light Rain (RV)
Avalanche Details
Avalanche Details:
Date and Time of Avalanche:
Friday, April 5, 2019 - 14:30
