More than two thirds of European cities are regularly confronted with climate change induced disasters. Early Warning Systems (EWS) play a crucial role in mitigating the effects of such disasters by detecting conditions which forecast the onset of a catastrophe and to compute its impact. EWSs provide alarming, decision support and information services to governments, companies and the general public.The UrbanFlood project creates an internet based hosting platform for EWSs. The EWS platform is run as an Internet service and connects via the Internet to sensor networks, to online sources of information and other EWSs. The platform is able to host multiple EWSs, corresponding to various hazards and belonging to different organizations. Through the Internet, additional computer resources required by the EWS platform are made available on demand. Artificial intelligence technologies detect alarming conditions in the objects monitored. In an alarming situation, a decision support system, making use of computational models of the physical environmental, informs stakeholders about the developing catastrophe. The core of the EWS hosting platform is a Common Information Space (CIS). The CIS is run as an online service, supports web service technologies and connects via the internet with other CISs. The EWS is also able to process simulated (data), turning the EWS into a simulator with which disaster mitigation scenarios can be developed and personnel can be trained.UrbanFlood validates the EWS framework in the context of dike failures and ensued flooding in an urban environment. Dikes are equipped with sensor systems and the EWS service is built up from a series of dike failure and flooding specific modules, including 3D/pseudo 4D dike evolution and flood-spreading models. Soon after the start of the project dikes in major European cities will be monitored.UrbanFlood investigates to which extent it is feasible to remotely monitor dikes and floods from other countries and continents.