In this Session, we will concentrate on flood events with duration less than 24 hours and on catchments with drainage areas less than a few hundred km squares. Progress in flash flood observations, modelling and forecasting , with uncertainty estimation through innovative observation concepts and improved process undoerstanding will be the main focus of the session. In particular, methods are sought to deal with short lead times and limited data availability involved in flash flood forecasting.

The session will also focus on innovative techniques for extreme precipitation estimation and now-casting at small space-time scales and observations and modelling of rainfall-runoff dynamics during flash flood events. The social impacts of these floods is also of great importance.
Contributions could cover:
i) use of radar, lightning, satellite and storm tracking monitoring technology to estimate rain rate for heavy rainfall events, and its uncertainty;
ii) use of remote sensing, real-time modelling and in situ measurements to estimate soil moisture at the onset on an event;
iii) analysis of the atmospheric and hydrologic controls on flash flooding, change of dominant process types with flood severity, threshold values and their relation to catchment characteristics;
iv) use of findings from post-event field campaigns for inference of runoff peaks and timing at multiple site on the river network, and methods for interpretation of these data;
v) sediment dynamics during flash-flood events; and
vi) societal impacts and the application of the above concepts in flash flood risk management.