Spatial and Temporal Variability of Meltwater Infiltration and Warming in a Maritime Snowpack over Wolverine Glacier, Alaska

Liquid water is the primary mechanism that warms the snowpack, providing both advective heat transport as it percolates and latent heat release when it re-freezes. Liquid water pathways through seasonal snow are complex because, as liquid water flows through snow, snow grains and snowpack structure are modified, and as a result, water pathways are altered. Previous studies have focused on warming and infiltration of liquid water in the snowpack by installing a single vertical profile in snowpacks less than 2 m thick. In this study, we installed four strings vertically (50 m apart) with 7-8 thermistors each within a 5 m-thick maritime snowpack on Wolverine Glacier in the Kenai Peninsula, Alaska. The installation of multiple temperature strings captures the spatial and temporal variability of snowpack warming and the infiltration of snow meltwater into the spring snowpack.

We observed two distinct warming and infiltration patterns between the installation date (May 13, 2021) and the snowpack becoming isothermal (June 2 +/- 5 days). During the first event (lasting 3 days), the first pattern was progressive warming from the top-down. The second pattern was a 'skipping' pattern, where deeper depths warmed up quicker. This suggests preferential flow bypassing part of the snowpack, then pooling and refreezing at greater depths with the associated release of latent heat. During the second event (over 6 days), two strings showed the top-down warming pattern and became completely isothermal on June 2. In contrast, the two other strings showed the 'skipping' pattern and became completely isothermal four days later, on June 6. These results demonstrate that one vertical profile is insufficient to capture the spatial and temporal variability of water movement, snowpack warming, and evolution to isothermal conditions.