Hydrometeorology of the catastrophic Blanco river flood in South Texas, May 2015

Meteorological observations, high-resolution rainfall estimates, and physics-based distributed hydrological modeling provide the opportunity to examine the hydrometeorological mechanisms accompanying the extreme storm and subsequent flood. Additionally, transpositions of the radar rain fields forced through the hydrologic model allow for analysis of the effect of position of the centroid of the storm relative to the catchment on floodwave propagation. Two major controls on the flood response are identified and analyzed: the position of heavy storm cells over the headwaters with subsequent slow movement downstream and the extremely moist antecedent conditions prior to the onset of the event.