Abstract: To assess current situation properly is crucial for effective decision-making in crisis management. However, gathering accurate information from incidence sites and providing appropriate support for assessment practices faces several challenges. The unique information demands of each crisis situation, the information availability or inter-organizational problems and obstacles to information exchange are important factors that need to be considered in designing ICT. In this contribution we present results from an empirical study about decision-making practices in scenarios of medium to large power outages in Germany. We focused on the needs and practices on information exchange at the level of inter-organizational cooperation. We examined the cooperation of fire departments, police, public administration, electricity infrastructure operators and citizens. Our empirical material reflects particularly conditions and challenges in current situation assessment practices, and we were able to derive design requirements for an inter-organizational situation assessment client as a complementary tool for existing crisis management infrastructures. © 2012 ISCRAM.