Forecaster Observation - Doris Creek, Swan Range

Location Name: 
Forecaster Observation - Doris Creek/Blaine Mountain, Swan Range
Swan Range - East Side (Hungry Horse Reservoir access)
Date and time of observation: 
Thu, 03/17/2016 - 12:00
Location Map: 

Red Flags: 
Recent loading by new snow, wind, or rain

Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

From 5:00 am to 8:00 am Noisy Basin SNOTEL recorded 0.5 inches of SWE and 7 inches of snow. Our objectives today were to assess the reactivity and distribution of new wind slabs and potential storm slabs within the new snow. We also wanted to look for surface hoar and/or weak, faceted snow around crusts in the upper snow pack, and affect of the new load. 

Below about 6500 feet we found about 16 inches of recent snow a top a crust that supported the weight of a snowmobile. The new snow was mostly cohesionless except where light wind drifting and sun exposure formed a soft slab. Along the ridgeline at and above 7000 feet we noted slabs that were more firm and produced some localized cracking. We dug a snow pit at 7000 feet on an east-southeast aspect and found multiple crusts in the top 4 feet of the snow pack. Several of these crusts had weak, faceted snow forming around the crusts. We did multiple stability tests to assess the reactivity of these crust/ facet combos and the results are as follows (video):

1) Recent snow/old snow interface, 40 cm from the surface - ECTN 13, ECTN 13, ECTP 15

2) Small, facets below March 13 crust, 60 cm from the surface - ECTP 24, ECTP 24

3) Layer of large facets, graupel, and decomposing surface hoar above late Februray crust, 70 cm from the surface - ECTP 24, ECTP 29 

Finally, we observed large monster cornices hanging above the east facing slopes of Blaine Mountain (image).

Snowpack photos: 
Snowpit videos (tests, etc): 

March 17, 2016 - Doris Creek, Swan Range

Weather Observations
Blowing Snow: 
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Light (Twigs in motion)
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 

Temperatures hovered right around freezing above 6500 feet. Intermittent clouds and light breeze kept the snow surface from becoming moist. Very small roller balls formed on steep slopes  at upper elevations late in the day.