In the hydrological sciences, forward-looking analyses such as forecasts, predictions, scenarios, outlooks and foresights are increasingly used for decision-making. These analyses come in many shapes and forms: short-term, long-term, local, global, model-based and scenario-based are but a few of these. Applications are many and include forecasting of floods and droughts, of seasonal availability of water and energy, and prediction for climate change adaptation.

Hydrology for decision-making, however, has an uneasy role as predictive uncertainties may be large: future boundary conditions are unknown, model parameter values may not be optimal and the system considered may change over time, thus invalidating the model used. Uncertainties and the implications of uncertainties need to be communicated to better inform decisions and prepare emergency response measures.

This session aims to contribute to a better understanding of the role and value, benefit and usefulness of different types of predictions in decision-making and emergency preparedness and response. ‘Predictions’ may include different types, e.g. deterministic forecasts, probability forecasts, scenario-based forecasts and outlooks, etc., and target different time scales (short-term, medium-term or long-term) and different spatial scales (from local to regional and global scales). This session welcomes real-world examples showing both, successes and failures on the effective use of hydrological forecasts in communication, decision-making and emergency response. Contributions addressing risk-based decision-making, as well as science and operational developments aiming at providing best practices and guidance on how to communicate forecasts in times of crisis or under uncertainty to different users are also welcome.

Contributions are solicited from scientists, decision-makers and policy analysts in the field of communication, decision making and emergency response to hydrological predictions, including water resources management, natural hazards (e.g., floods and droughts), management of rivers and deltas, and climate impacts.