Item: FIELD IDENTIFICATION OF LONG-TERM TRENDS IN MIXED FORMS: A COMPARISON OF PHOTO ANALYZED GRAINS AND MORPHOLOGICAL PROCESSES OBSERVED BY SNOWPACK
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Title: FIELD IDENTIFICATION OF LONG-TERM TRENDS IN MIXED FORMS: A COMPARISON OF PHOTO ANALYZED GRAINS AND MORPHOLOGICAL PROCESSES OBSERVED BY SNOWPACK
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Claire G. Bicknell [ Alaska Pacific University, Anchorage, AK, USA ]
- Eeva Latosuo [ Alaska Pacific University, Anchorage, AK, USA ]
Date: 2026-09-28
Abstract: Rounding Faceted Particles (FCxr) and Faceted Rounded Particles (RGxf), previously known as mixed forms, are unique in that they are categorized by both shape and metamorphic processes. This study investigates whether in-field practices that use corner shape to infer metamorphic processes can reliably determine whether a grain is faceting or rounding. This was tested by comparing photo-analyzed corners of grains in the field to metamorphic processes simulated by SNOWPACK. Over an 8-week period in the Talkeetna Mountains of Alaska, four layers of mixed forms were tracked across 16 samples in a study plot. Corner angles of the individual grains were then measured from high-resolution photographs and classified using a threshold angle of 119.1° derived from an expert-classified grain library. The corresponding layer processes were then modeled using SNOWPACK, with representative meteorological inputs from weather models and nearby stations. A logistic regression analysis found the lack of a statistically significant relationship between corner angle classification and modeled metamorphic behavior (p = 0.215), and a low agreement rate of 47% between angle-based and simulated classifications. These results suggest corner angle alone may not be a reliable indicator of metamorphic processes in the field. These findings suggest field classifications of mixed forms should prioritize grain shape over the inferred process. Field observations may still provide valuable morphological insights, but interpreting metamorphic processes likely requires a combination of observations, weather history, and simulation tools.
Object ID: ISSW2026_P4.10.pdf
DOI: https://doi.org/10.15788/1790099259
Language of Article: English
Presenter(s): Claire Bicknell
Keywords: Faceted Round Particles, Rounding Faceted Particles, Metamorphosis, SNOWPACK
Page Number(s): 443 - 449
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