Introduction. Climate change and anthropogenic activities are transforming the natural environment. The hydrological consequences of extreme impacts on landscapes that cause significant disturbances or complete destruction of soil and vegetation cover in river basins, such as forest fires or mining activities, have not been sufficiently studied. Purpose of the research. The objective of this study is to assess changes in water and suspended sediments flow in mountainous permafrost river basins as a result of a forest fire using six sites in the Vitim River basin as an example. Materials and methods. Using MODIS remote sensing data, the relative shares of river basin areas affected by intense fires in the spring and summer of 2003 were identified and quantified. To assess the impact of the fire on the hydrological regime, daily water discharges, daily precipitation layers for fourteen meteorological stations, as well as data from the hydrometeorological network on suspended sediment discharges were used. Results. The areas affected by fires ranged from 46% in the Amalat River basin (F=2100 km2) to 78% in the Vitimkan River basin (F = 969 km2). Analysis of daily water flow and precipitation data for the period 1966–2012 and decadal suspended sediment discharges for the period 1980–2013 before and after the fire in 2003 showed that two of the three basins affected by the fire experienced a sharp short-term increase of streamflow, however, these changes could only be detected when significant amounts of liquid precipitation fell. Discussion. The effect of the fire on suspended sediment runoff is observed for 4–6 years after the fire and is manifested in an increased sediment runoff compared to the conventionally “stationary” period for the entire range of changes in water discharge. Conclusion. Although the nature of changes in water and sediment runoff at plot sites and in river basins after the fire are consistent, the absolute values of erosional loss obtained at the plots are very high and cannot be directly extrapolated to the scale of basins, even if the latter were affected by the fire over a large area. The results obtained can be used to predict runoff characteristics in disturbed landscapes of various origins.