Surge-type glacier activity in the Tajik Pamirs from 2000 to 2024

Surge-type glaciers are a common feature in the Tajik Pamirs, yet their distribution, temporal recurrence, and surge characteristics remain poorly understood. Through multi-sensor observations from Landsat, PlanetScope, and unmanned aerial vehicles (UAVs) surveys covering the period from 2000 to 2024, we assembled a comprehensive inventory of 507 surge-type glaciers with a total area of 3685.1 ± 41.8 km 2 . Among these, 96 glaciers (totaling 1441.8 ± 15.4 km 2 ) exhibited active surging during the observation period. These surging glaciers are predominantly clustered in the Mughob and Khingov basins, and preferentially occur in valley and compound-valley glaciers with northerly aspects, highlighting the potential importance of topographic controls on surge susceptibility. Temporal analyses indicate pronounced variability in surge timing and duration during 2000–2024, with several glaciers exhibiting long-lived active phases that were already underway at the beginning of the observation window. Recent surge activity tends to be shorter-lived or intermittent compared to earlier prolonged surges, likely reflecting reduced accumulation and enhanced melt that limit mass supply under recent climatic conditions. Observed surge durations range from multi-year active phases (typically ~4–15+ years) to shorter-lived accelerations lasting several months to a few years (typically up to 2–3 years). Surges transfer mass downslope, reorganize subglacial hydrology, and facilitate the formation of supraglacial and ice-dammed lakes, thereby amplifying the likelihood of glacier-lake interactions and related hazards. Our findings suggest that the Pamirs remain a global hotspot for glacier surging in the early 21st century. However, the recurrence patterns of surges appear to be evolving under recent climate conditions, highlighting the need for longer observational records to robustly assess long-term trends.