Drought-flood transitions across different hydro-climates

Drought-flood transitions greatly challenge water management and the development of adaption measures to extreme events. These transitions can occur rapidly but may also take many months or years and are often studied using climate instead of streamflow data – neglecting the role of surface processes. The time between one extreme and the other may depend on climate and catchment characteristics including topography, soil types and water use. However, it is yet unclear how drought-flood transition times vary regionally in dependence of climate characteristics, flow processes, and water storage.
In this study, we analyse how drought-flood transition times vary across different hydro-climatic zones. We show how transition times, i.e. the number of days between drought-termination and the following flood event, vary in space. We identify indicators and common patterns of rapid transitions by correlating drought and flood characteristics to transition times. To do so, we use large-sample datasets such as CAMELS and LamaH, which provide diverse catchment characteristics in addition to streamflow data. This information helps to identify catchments with a high likelihood of abrupt drought-flood transitions. Such identification is highly relevant because flood preparedness is often low during drought events, which potentially increases the severity of flood impacts.