This　study　advances　the　dynamic　assessment　of　flash　drought　(FD)　by　extending　the　voxel-based　three-dimensional　FD　(V3DFD)　framework　developed　previously　to　improve　tracking　the　FD　trajectory　and　measuring　the　migration　distance.　We　apply　the　extended　V3DFD　to　evaluate　the　spatiotemporal　evolutions　of　FD　during　1980–2020　in　three　river　basins　in　China:　a　semi-arid　to　semi-humid　Yellow　River　Source　basin　(YRSB),　a　semi-humid　to　humid　Huai　River　basin　(HRB),　and　a　humid　Xijiang　River　basin　(XRB).　Our　results　indicate　that　the　extended　V3DFD　method　can　effectively　capture　the　entire　lifecycle　and　migration　patterns　of　FD.　The　humid　XRB　is　prone　to　severe　FD　events,　characterized　by　long　migration　distances　and　durations,　large　spatial　coverage,　and　mainly　starting　in　August　and　October　and　ending　in　November.　In　contrast,　FD　events　in　arid　basins　have　shorter　duration　and　migration　distance,　lower　severity,　smaller　affected　area,　but　higher　frequency,　with　most　events　occurring　in　the　first　half　of　the　year.　Precipitation　deficit　is　responsible　for　early　FD　development　in　all　basins.　The　FD　development　in　YRSB　is　typically　accompanied　with　large　evaporation　caused　by　strong　wind,　while　that　in　HRB　mainly　attributed　to　high　temperature.　Low　relative　humidity　has　a　more　significant　impact　on　FD　in　wetter　basins,　leading　to　higher　evaporative　demand　dominating　FD　development　in　XRB.　It　is　also　found　that　shallow　soils　in　XRB　accelerate　SM　depletion,　while　prolonged　snowmelt　in　YRSB　increases　FD　sensitivity　to　runoff　partitioning　parameters,　highlighting　the　role　of　climate-hydrology　interactions　in　modulating　FD　dynamics.　©　2025　Elsevier　B.V.