Field Report
Gunnison - CO
Report Information
The goal of today's fieldwork was to gauge the sensitivity and size of avalanche problems in sheltered areas on the north half of the compass by selecting small, low-consequence test slopes. Avalanches were easy to trigger on small test slopes on north and easterly aspects. Even though slabs were only a foot thick, the entrainment of the old snow below made for larger-than-expected debris piles. We did not travel near any wind-drifted slopes, but natural activity on Schuylkill Ridge suggested that more cohesive slabs were forming in wind-affected areas. Riding conditions were very nice on modest slope angles around 30 degrees. We experienced a few quiet collapses and cracking on steep terrain features. We skied several small, low-consequence slopes, looking for feedback on avalanche conditions. We triggered 3 small avalanches breaking on the weak facets below this weeks snow.
Observation from CBAC database
CBAC Northwest zone
Snowmobile ride out the Slate River to Pittsburg. Tour around Pittsburg area.
Avalanches
Visibility was poor, but we could see two natural avalanches immediately below Schuylkill Ridge. There was enough propagation in these wind-drifted avalanches to make them difficult to manage, and it would best to avoid drifted terrain. We intentionally sought out small test slopes in sheltered terrain to get feedback on the developing Persistent Slab problem on northerly slopes and were able to find sensitive avalanche conditions. The entrainment of old snow created debris piles bigger than one might expect from foot-thick, soft slabs.
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Date | # | Elev | Asp | Type | Trig | SizeR | SizeD | Problem Type | Location |
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12/27/2024
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1 | <TL | N | SS | AS/c | R1 | D1 | Persistent Slab |
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Date and Time
12/27/2024 -
12:00pm
(estimated)
Location
38.941
-107.072
Start Zone Elevation
10,400 ft
Area Description
Pittsburg Rollers area
Avalanche Comments
A small avalanche breaking on weak facets below this week's storm snow. I saw very small surface hoar (5mm) sitting above the facets at this location. There was a small amount of drifting from last night but the slab was still fist hard. |
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12/27/2024
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1 | TL | NE | SS | N | D1.5 | Persistent Slab |
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Date and Time
12/27/2024 -
12:00pm
(estimated)
Location
38.941
-107.072
Start Zone Elevation
11,400 ft
Area Description
Schuylkill Ridge - FAY
Avalanche Comments
This natural avalanche likely ran early in the morning, but possibly on 12/26. I made the best guess on size at D1.5 but it could be D2 with available old snow for entrainment. |
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12/27/2024
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1 | TL | NE | SS | D2 | Persistent Slab |
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Date and Time
12/27/2024 -
12:00pm
(estimated)
Location
38.941
-107.072
Start Zone Elevation
11,400 ft
Area Description
Schuylkill Ridge - Great Wide Open
Avalanche Comments
This natural avalanche was visible at 10 am. It likely failed in the early morning hours. Visibility was poor, so size is the best estimate, but given the entrainment of old snow, I coded it as D2, large size. |
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12/27/2024
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1 | <TL | NE | SS | AS/c | D1 | Persistent Slab |
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Date and Time
12/27/2024 -
12:00pm
(estimated)
Location
38.941
-107.072
Area Description
Pittsburg Cabin Shot
Avalanche Comments
We intentionally triggered this avalanche on a smaller test slope. The entrainment of old snow made up a large portion of the debris. This avalanche broke about 100 feet wide. |
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12/27/2024
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1 | <TL | NE | SS | AS/c | D1.5 | Persistent Slab |
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Date and Time
12/27/2024 -
12:00pm
(estimated)
Location
38.941
-107.072
Start Zone Elevation
10,300 ft
Area Description
Pittsburg Cabin Shot
Avalanche Comments
It was intentionally triggered on a smaller test slope. Entrainment of old snow was notable and likely added more volume to the debris than the slab. |
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Multiple Avalanches
Snowpack
At 230 pm, around 14 inches of recent snow sat above a faceted snowpack. Collapsing was quiet and relatively infrequent, and cracking traveled up to 20 feet. Traveling above and skiing a few small test slopes, it was easy to trigger slab avalanches. Avalanches entrained lots of old snow as they ran and would have easily reached a large size on longer slopes.
Precip rates were relatively slow while we were in the field, and it felt like the snowpack in sheltered areas was near but short of natural avalanche activity. I suspect a brief period of strong snowfall would have tipped the snowpack over the edge in sheltered areas on the north half of the compass.
Weather
Light snowfall during our tour. About 2 inches accumulated during the 5 hours in the field. Winds remained light at our below treeline elevation with minimal transport near valley bottom.