In this paper we describe a disaster management system. It is assumed that each individual in the field is equipped with a PDA (Personal Digital Assistant) and that can communicate with other PDAs in the vicinity. Together the PDAs form an ad-hoc network. Users can enter their own observations to the PDA and like the position of victims and or a description of the current situation at particular location (e.g. smoke and emergency exits and traffic congestion). This information is entered in a special iconic language. Reversibly and the PDAs inform the users on the overall current situation of the crisis. In order to come to a shared view of the world and the knowledge that is present in the network has to be shared and fused. The proposed way to communicate is via a shared blackboard. This approach facilitates communication in a time and place independent way.