COST funding allows European scientists establish international links, communicate their work to colleagues and promote international research cooperation. COST731 was established to study the propagation of uncertainty from hydro-meteorological observations through meteorolgical and hydrological models to the final flood forecast. One focus is on how information about uncertainty is presented to the end-user and how it is used. COST731 has assembled a number of demonstrations/case studies that illustrate the variety of practical approaches and these are presented here. While there is yet no consensus on how such information is presented, many end-users do find it useful.