The World Meteorological Organization (WMO) is advocating for national hydrometeorological services to implement impact-based forecasts and warnings, to make warnings more meaningful. These are warnings that are triggered on the potential impacts of a weather event (such as trees falling and power outages), rather than on the hazards themselves (such as wind speed thresholds). However, little research has investigated the effectiveness of this type of warning. In this webinar, Sally Potter gives us an overview of her research on this, as well as on the challenges and benefits from an institutional perspective. Effective warnings are those that prompt an appropriate behavioral response in a timely manner and agencies need to go beyond simply issuing a forecast or warning, as we move towards the UN initiative of Early Warnings for All.