Field Report
Aspen - CO
Report Information
The weak layer is not very weak and the slab is mostly discontinuous across the terrain after the extended dry spell weakened it on most northerly slopes. We had to hunt to find slopes where you might be able to trigger an avalanche and found them on partially wind-loaded terrain features between 11,000 and 12,000 feet on shady slopes in West Willow Creek. Even on these slopes of concern, where there is a prominent weak layer and a cohesive overlying slab, snowpack tests show mixed results from easily propagating failures to stubborn propagating failures to non-propagating failures.
Baldy, West Willow Creek
Snowmass ski area to Baldy Mountain into West Willow Creek and back into the ski area
Avalanches
Observed dozens of large to very large avalanches from the Thanksgiving Storm natural avalanche cycle. Only avalanches observed in West Willow, Willow, and East Snowmass Creeks were included in this observation.
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Date | # | Elev | Asp | Type | Trig | SizeR | SizeD | Problem Type | Location |
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11/27/2024
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4 | >TL | NE | SS | N | R2 | D2.5 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
south of Willoughby Mountain above the headwaters of East Snowmass Creek |
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11/27/2024
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1 | >TL | N | SS | N | R3 | D2 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Avg Width
3,000 ft
Area Description
northerly-facing slopes in the basin directly south of Baldy and east of Peak 13244 feeding into Willow Creek
Avalanche Comments
Incredible propagation across many terrain features for nearly 3000 feet. |
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11/27/2024
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1 | TL | NE | SS | N | R3 | D2 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
Lower down Willoughby Ridge above East Snowmass Creek |
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11/27/2024
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1 | >TL | SE | SS | N | R1 | D2 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
Garrett Peak |
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11/27/2024
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2 | >TL | NE | SS | N | R1 | D2 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
northeast slopes of Willoughby Mountain |
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11/27/2024
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1 | >TL | N | SS | N | R2 | D2.5 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Start Zone Elevation
13,300 ft
Area Description
Buckskin Benchmark
Avalanche Comments
The avalanche spanned wall-to-wall across the entire north face |
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11/27/2024
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2 | >TL | NW | SS | N | R2 | D2.5 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
Sievers Mountain into Willow Creek
Avalanche Comments
Two different avlanches: one avalanche propagated across three separate gullies connecting three different avalanche paths, the second avalanche propagated across at least two gullies then out of sight. |
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11/27/2024
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1 | >TL | N | SS | N | R2 | D2.5 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
Sievers Mountain south above Willow Creek
Avalanche Comments
Impressive propagation with the crown spanning over 2000 feet across multiple terrain features. |
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11/27/2024
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1 | >TL | NW | SS | N | R2 | D2 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
above Willow Lake west of Sievers Mountain south |
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11/27/2024
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1 | >TL | NE | SS | N | R1 | D1.5 | Storm Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
Willoughby Ridge |
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11/27/2024
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1 | >TL | E | SS | N | R1 | D1.5 |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
east-facing slope in the basin directly south of Baldy and east of Peak 13244 feeding into Willow Creek |
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11/27/2024
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1 | >TL | E | SS | N | R2 | D2.5 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Avg Width
3,200 ft
Area Description
Willoughby Ridge
Avalanche Comments
The avalanche propagated a kilometer wide |
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11/27/2024
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1 | >TL | E | SS | N | R1 | D1.5 | Persistent Slab |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
Omega Cliffs, West Willow Creek |
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11/27/2024
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2 | >TL | NW | SS | N | R1 | D1.5 |
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Date and Time
11/27/2024 -
12:00am
(estimated)
Location
39.148
-106.965
Area Description
Bighorn and another one west of Coulter's Crack, West Willow Creek |
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Multiple Avalanches
Snowpack
Minor cracking on wind-drifted snow along ridgelines. The snowpack above treeline is very wind-affected with ski and boot penetration often 0 cm with a variable breakable wind crust up to 8cm thick. The near treeline elevation band, roughly between 11,000 and 12,000 feet seems to be the area of most concern where the slab is mostly continuous, close to two feet thick, and rests on a weak layer of faceted grains that showed mixed results in snowpack tests. Although these areas of concern with a slab over a weak layer are getting harder to find and growing more stubborn there are still slopes I would avoid traveling on, especially near treeline and the lower levels of the above treeline elevation band. West Willow Creek also notably did not have any depth hoar present in the areas where we dug and any facets near the ground showed clear signs that they had been rounding for an extended period of time and were well-bonded and mostly rounded. Below about 11,000 feet small surface hoar grains were present on most slopes except for steep, sunny slopes where any surface hoar growth overnight was likely melting in the daytime.
Weather
Few clouds and mostly calm with light gusts from the southwest. No noticeable snow transport today.