Quantifying snow duration in small-scale Arctic drainage features above continuous permafrost

The thawing of Arctic permafrost mobilizes previously sequestered carbon, amplifying positive feedback in the global climate system. Thaw patterns are heterogeneous and influenced by factors such as snow insulation and hillslope hydrology, including narrow (<10 m) features like water tracks (WT) and thermoerosional gullies (TG). These WT/TG features are distinguished by vegetation, soil moisture, and drainage patterns, yet their snow duration characteristics remain poorly understood. We applied the Blue Snow Threshold (BST) algorithm to high-resolution PlanetScope imagery (3 m) from 2017 to 2023 to quantify snow-on, snow-off, and snow cover duration for 34 field-delineated WTs and TGs on the North Slope of Alaska, USA. BST-derived snow duration metrics were compared to those derived from in situ time-lapse photographs. BST-derived results indicate that snow-on dates are similar between hillslopes and WT/TG features, while snow-off dates are delayed on average by 19 days in WTs and 32 days in TGs. Results from in situ photographs suggest a smaller offset in snow-off dates, 9 days on average, highlighting limitations of the remote sensing data’s temporal resolution. These findings suggest that WTs and TGs hold snow longer than the surrounding hillslope, which could facilitate their remote identification and clarify their contributions to permafrost thaw.