Investigating Ice Layer Dynamics and Hydrological Processes in Snowpacks Using Ground Penetrating Radar and Energy Balance Analyses

This study examines the formation, evolution, and hydrological role of ice layers in snowpacks during dynamic winter conditions, with a focus on liquid water infiltration, moisture redistribution, and structural transformations. The research was conducted at the Sainte-Marthe Experimental Watershed (BVE), located 70 km west of Montreal, Quebec, Canada. From February 8 to April 3, 2023, the study captured 50 freeze-thaw cycles and 7 substantial rain-on-snow (ROS) events, which significantly influenced snowpack properties and hydrological behavior.

 A downward-looking Ground Penetrating Radar (GPR) system was used to provide high-resolution data on snowpack stratigraphy and changes in dielectric properties. Complementary observations, including ultrasonic snow depth sensors, Time-Domain Reflectometry (TDR) probes, and weekly snow pit measurements, supported the GPR interpretations. These data were further contextualized with energy balance analyses to link external meteorological drivers—such as radiative fluxes and precipitation inputs—to internal snowpack processes.

 The results highlight the critical role of ice layers as dynamic hydrological barriers. During a significant ROS event, March 17, the GPR captured a rapid increase in two-way travel time (TWT) and amplitude changes as liquid water accumulated above an impermeable ice lens. Over time, the lens degraded, becoming permeable and enabling deep water infiltration. This permeability shift was corroborated by amplitude data, which revealed contrasting moisture responses above and below the lens. Four other events monitored before and after March 17 served in capturing the evolving influence of ice layers in influencing surface meltwater retention and subsurface flow pathways.

By emphasizing the hydrological dynamics of ice layers, this study advances understanding of snowpack behavior under changing winter conditions. The integration of GPR, field measurements, and energy balance analyses provide a powerful framework for examining the interplay between meteorological inputs and internal snowpack transformations, particularly during critical events involving ice layers.