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Observation: White Pine Gulch

Observation Date
1/12/2018
Observer Name
Bruce Tremper
Location Name or Route
White PINE
Weather
Sky
Overcast
Wind Direction
West
Wind Speed
Moderate
Snow Characteristics
Snow Surface Conditions
Dense Loose
Snow Characteristics Comments
New snow amounts from the last storm were extremely elevation dependent with rain from the last storm falling below about 8,500' and rapidly increasing snow amounts as you travel higher. The snow was graupel, stiff and spongy but it rode very well at mid elevations. There's only a skiff at the trailhead and up to about 5 inches at 9,500' but the wind damaged everything up higher in the bowl when you get above tree line. The elevation band for good riding seems to be between 8,500' and 9,500' with wind damaged snow above 9,500'. Very few people out today. Surprisingly, we saw only one other person out today, a solo snowshoer in White Pine and we broke trail all day except when we followed the snowshoer track down the road. I ascended through the trees near the creek but I wouldn't recommend it because the snowpack is still very thin and there's lots of downfall and alder to negotiate. Better to stick to the road, which is the way we came down. We ascended to just below White Pine Lake in the upper cirque.
Red Flags
Red Flags
Recent Avalanches
Wind Loading
Collapsing
Poor Snowpack Structure
Red Flags Comments
In contrast to what we saw in Beartrap yesterday, we experienced about a half dozen large collapses on the flats between 8,500 and 9,500'. We saw a number of avalanches that occurred during the storm, NW, N and NE facing between those same elevation bands. We couldn't see any recent avalanches in the upper bowl above 9,500' perhaps because the strong winds have removed much of the snow there and any avalanches that may have occurred there are now stripped away or buried under fresh wind drifts. We were thinking of breaking a trail through the woods up to the Spire but after feeling many collapses and digging a couple pits, I chose to seek more conservative terrain. There's widespread monsters in the basement.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #1 Comments
I'm not sure whether you would call this deep, persistent slab or persistent slab. But since everything is collapsing on the basal depth hoar on the ground with several storm layers above it, I will call it a deep slab although with our shallow snowpack, they are breaking out only 1 to 2 feet deep. I dug 4 different snowpits on NW, N, NE aspects between 8,500 and 9,500' and all propagated on easy elbow taps on the basal depth hoar on the ground. One snowpit had the rain crust intact near the surface but you don't see any more rain crust when you get above about 9,000'. They all broke very similarly. I avoided any slope approaching 30 degrees or steeper.
Comments
I dug 4 different snowpits on NW, N, NE aspects between 8,500 and 9,500' and all propagated on easy elbow taps with an extended column test on the basal depth hoar on the ground. One snowpit had the rain crust intact near the surface but you don't see any more rain crust when you get above about 9,000'. They all broke very similarly. I avoided any slope approaching 30 degrees or steeper. Total snowpack depth is 2 to 3 feet deep.
We found one natural avalanche that ran during the storm that crossed the White Pine road just on the up canyon side of Columbine Bowl (aka Birthday Chutes). It broke about 1.5 feet deep on a 40 degree, NW facing slope at 8,800' and was about 150' wide. Here, Susi is standing on the road with the avalanche above.
We also saw widespread avalanche activity on other slopes in that elevation band. This avalanche ran during the storm around 9,000', about 2' deep, 1000 feet wide crown face, 40 degree steepness, NE facing on a low spur ridge of Lake Peak and this is not too far above the creek.
More avalanches during the storm on E facing slopes, 2' deep, 500' wide, 40 degree steepness. 9,000'.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable