Managing the disaster response, involving many heterogeneous organizations, challenges information system support for coordinating their activities. Current means for coordination such as e-mail exchange, white boards, phone or web-based mission diaries provide only very limited support. One problem is managing the temporal coordination of the response activities of different organizations to unify and synchronize their efforts. It is important that activities can be flexible defined and that each organization can integrate activities of other organizations into their plans. This implies also that several coordinators in different organizations exist. The status and awareness of activities as well as conflicts, when coordinating them, needs to be provided to all interested stake holders in real-time. We provide a model and a system to support this scenario. It is implemented in the Google Wave collaboration infrastructure based on open standards.