Item: MULTI-SEASON COMPARISON BETWEEN SMP, SNOW SCOPE, AND RAM PENETROMETERS
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Title: MULTI-SEASON COMPARISON BETWEEN SMP, SNOW SCOPE, AND RAM PENETROMETERS
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Coleman Kane [ Department of Geosciences, Boise State University, Boise, ID, USA ]
- Kelly Elder [ U.S. Forest Service, Rocky Mountain Research Station, Fort Collins, CO, USA ]
- HP Marshall [ Department of Geosciences, Boise State University, Boise, ID, USA ]
- Katherine Gura [ Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, CO, USA ]
- Dylan Elder [ Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, CO, USA ]
Date: 2026-09-28
Abstract: Evaluating snow hardness is an important component of assessing avalanche hazard. Persistent slab problems can often be identified from hard-over-soft layering in manual snow profiles. The hand hardness scale is the most common method for measuring hardness, but it can be subjective and requires the time and labor-intensive process of digging snow pits. However, it is a key metric in the yellow flag indices, a parameter checklist used to identify potential persistent slab avalanche instability from manual snow profiles. Cone penetrometers provide a more objective alternative to the hand hardness scale, allowing practitioners to increase spatial and temporal sampling and minimize observer bias. The ram penetrometer has long been an industry standard, and measures penetration resistance with repeated blows from a hammer. The SnowMicroPen (SMP) is a high-resolution (4μm) digital cone penetrometer that measures resistance force at a much higher resolution (0.01 N) than the ram, as it is driven through the snow at a constant speed. The Snow Scope is a relatively newer instrument designed specifically for use in the backcountry. The instrument folds into the user's backpack similar to an avalanche probe and displays profiles on a smartphone via Bluetooth connection. Using two seasons of coincident field measurements (174 ram profiles, 357 SMP profiles, 714 Snow Scope profiles), we evaluate and compare all three penetrometers' ability to detect changes in hardness and accurately measure the hardness of soft layers. Additional consideration is given to evaluating the depth repeatability of the Snow Scope. We show the Scope performs similarly to the SMP in both depth estimation and measured force, and that that the ram is still a relevant instrument.
Object ID: ISSW2026_P3.53.pdf
DOI: https://doi.org/10.15788/1790099217
Language of Article: English
Presenter(s): Coleman Kane
Keywords: Ram penetrometer, SnowMicroPen, Snow Scope, yellow flags, lemons, hardness, stratigraphy
Page Number(s): 2247 - 2254
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