Defined as the difference between the peak discharge and action stage discharge normalized by the flooding rise time and basin area as given in Eq.(1) and visualized in Fig. 1 of this paper: http://journals.ametsoc.org/doi/abs/10.1175/JHM-D-16-0082.1
The flashiness metric gives the rate of rise of the hydrograph during flooding conditions and thus captures both the magnitude and timing aspects with higher values corresponding to more severe floods.
Data has been resampled because of size restriction on RPubs server. This is a temporary visualization. A complete webpage displaying all variables will be published soon.