There is no point modelling hazards and risks if that information is of no use to decision makers (at both an individual and policy level including the scientific community, the public, governmental institutions, engineers, policy makers, emergency and resilience managers). We therefore have to ensure that we are providing the information that different stakeholders need, in a format and time frame that is of use to them, in a form that minimizes the possibility of misunderstanding or misperception, and that focuses on the needs of the respective stakeholder. In this session we aim at addressing the problems surrounding communicating hazard and risk of natural catastrophes. Important questions include: who are the key stakeholders for each kind of information that we can provide? What information does each require? How do we balance the trade-off between restricting the information provided to improve comprehension versus the ethics of withholding information? How to approach the boundary between providing information and providing advice? How do we communicate the different uncertainties (both epistemic and aleatory)? What can be learned about the communication of geospatially- and temporally-dynamic data from other fields (such as meteorology, military defence etc) and how should we communicate in ongoing crises, in particular during unexpected changes in the development of catastrophic events? How do we ensure our communications are trustworthy? What are the metrics of success in such communications? We will be considering all time frames and stages of hazard assessment from long-term maps and planning to emergency warning and rapid loss assessment when an event occurs. This includes all possible communication channels (e.g. scientific publications, public or press announcements, social networks, TV, radio, newsletters) and/or content types (e.g. text, video, graphics). We solicit contributions from all fields with the aim of bringing together a variety of researchers to share their experiences from their respective fields.