The data-scarce Varzob River basin, Tajikistan, shows significant cold-season warming, an earlier spring runoff shift, and a sharp rise in avalanche frequency. We analyse long-term runoff (1940–2018), meteorological records (2000–2024), avalanche observations (2019–2026), field snow surveys (2025–2026), and satellite/UAV imagery (2024–2025). Annual runoff shows a 6.7% higher mean in 1991–2018 than in 1940–1990, but the long-term trend is not significant (p = 0.23). However, the centre of mass of spring runoff shifted significantly earlier by 3.7 days (p < 0.001). Cold-season temperature increased significantly (p = 0.016), while wind speed showed no significant trend (p = 0.061). Snow water equivalent at seven elevations (1930–2955 m) ranges from 200 to 440 mm, and melt-freeze crusts indicate a snowpack prone to wet-slab avalanches. Avalanche frequency increased from 81 events in 2019 to 430 in 2025 and 560 (partial) in 2026, coinciding with a ~70% higher snow water equivalent in 2026. Mapped avalanche paths terminate less than 50 m from the Varzob River, suggesting a potential, though unquantified, contribution of avalanche snow to spring runoff. The integration of long-term hydrology, high-resolution meteorology, field surveys, and remote sensing offers a replicable framework for cryospheric-hydrological studies in data-scarce mountain basins.
Vosidov et al. (Thu,) studied this question.