The conventional monthly resolution of global gravity products from the Gravity Recovery and Climate Experiment (GRACE) and its successor GRACE Follow-On (GFO) greatly impedes their application to transient extreme climate events like floods. Nevertheless, this study utilizes the line-of-sight gravity difference between the twin GFO satellites, reflecting the instantaneous surface mass changes below, to obtain water mass changes at a resolution of days. This study investigates two floods in July 2021 in Western Europe and Central China (CC), respectively, and the high-resolution results present the temporal progression of the floods up to a maximum of about 40 Gt. However, the GFO-derived water gain in CC is much lower than expected. We speculate that intense human manipulation of water resources mitigated the repercussions of the flood in CC. This study presents the feasibility of GFO application in fast-evolving climate events and highlights the effectiveness of countermeasures by humans to flood hazards.