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Observation: Summit

Location: Manitoba treeline

Date:
Observer:
Route & General Observations

Common Manitoba skintrack up. At treeline, turned north to find a small S/SW facing slope for a pit. After digging the pit, rejoined the skintrack to the summit. Skied down the ridge to the north before dropping a line back to the trail out.

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Observer Comments

As mentioned in previous obs and the advisory, lots of several-day-old avalanches visible throughout the area. Most notably on all the east facing slopes of the mountains to the west of the highway all along the Summit Lake corridor.

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.
Weather

-16 C at the parking lot at 11:00a. Temps rose to -2 C in the subalpine at our pit ~2300' Skies clear all day, no precip. or cloud cover. Winds calm -> light mostly out of the N/NE

Snow surface

Soft settled snow. Starting to have some decent solar effects in the afternoon.

Snowpack

Snowpit @ 2300', S/SW aspect, 25 degree slope, HS: 150cm (dug to the ground)

Ground - 30cm: Fist, basal facets 2-3mm
30cm - 50cm: 4 Finger, faceting rounds/rounding facets(??) 1-2mm
50cm - 130cm: Pencil, solid consolidated snow
130cm - 140cm: 1 Finger
140cm - 150cm: Fist

-CTN
-ECTX, but when trying to clear out the block, a very slight pull with my shovel caused the whole column to come away as a single giant block, failing on the 30cm basal facets (picture #1)
-PST25/90End @ 30cm basal facets (picture #2, sorry about the shadows)

Pit and tests seemed to agree with advisory concerns of the 'low-likelihood/high-consequence' hazard. Went digging for basal facets and found them. Couldn't get them to fail in compression tests, but after initiating a failure, they propagated well and the slab would be quite large. Reaffirmed the need to watch out for potential thin spots in the snow pack where a skier could impact that layer and cause a mess.

Photos & Video
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