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Constraining snow water equivalent of wet snowpacks in southeast Alaska

Annals of Glaciology
By: , , , , , and 
https://doi.org/10.1017/aog.2025.10014

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Abstract

Quantifying snow water equivalent (SWE) with ground-penetrating radar (GPR) in a warming climate is complicated by the incidence and variability of liquid water in snow. Snow surveys conducted during the melt season serve as a valuable analog to conditions under future warming. Here, we determine the variability of wet snowpack properties (relative permittivity and density) to quantify their impact on SWE estimates using GPR. We collected spatially continuous snowpack measurements with 400 MHz GPR in 2012 and 2021 across repeat transects (~150 km each year) along with spring and summer snow depth and density measurements from snow pits and snow cores. Snow relative permittivity values ranged between 2.06 – 2.62 in 2012 and 2.11 – 5.11 in 2021, resulting in calculated volumetric liquid water content (LWC) between 1.7% – 5.7% in 2012 and 2.1% – 16% in 2021. This variability in snow relative permittivity results in SWE uncertainties between 8% – 33%, with more extreme cases reaching 13% – 45%. We attribute this uncertainty to spatial and temporal variability in liquid water content when using GPR to estimate SWE. As snowpacks become wetter with rising atmospheric temperatures, GPR surveys should include in-situ relative permittivity measurements to reduce depth and SWE interpretation uncertainties.

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Publication type Article
Publication Subtype Journal Article
Title Constraining snow water equivalent of wet snowpacks in southeast Alaska
Series title Annals of Glaciology
DOI 10.1017/aog.2025.10014
Volume 66
Publication Date July 14, 2025
Year Published 2025
Language English
Publisher Cambridge University Press
Contributing office(s) Alaska Science Center Water
Description e21, 9 p.
Country United States
State Alaska
Other Geospatial southeast Alaska
Additional publication details