Recent disasters, such as Hurricane Katrina in 2005, have shown several issues for coordination of human activities in these dynamic situations. Contemporary tools for coordination used in the disaster response, such as e-mail, Whiteboards or phone, only allow for unstructured coordination, which can cause coordination problems. Hence, we discuss current information systems for coordinating activities in a structured manner and identify their weaknesses in context of a process modeling effort conducted together with experienced disaster managers. Afterwards, we propose a framework for coordination of activities in dynamic situations. The framework presented in this paper has been implemented as an extension to an open collaboration service. This shows how it can be used in context of other tools required for disaster response management, such as maps, pictures or videos of the situation. The work described here is the foundation for enabling inter-organizational coordination of activities relevant in other domains, e.g. enterprise support processes, production processes or distributed software development projects. Furthermore, comments by disaster managers show that the concepts are relevant for their work. The expected impact is a more effective and efficient coordination of human activities in dynamic situations by structuring what needs to be coordinated.