Events like earthquakes, terrorist attacks, water contamination etc. have drawn an increased attention on the way crisis preparedness can be improved by citizens, authorities and society as a whole. Current research has highlighted the importance of social media in crisis communication and why social media are important, but neglects to describe how social media is used by public organizations during crisis situations. By studying a particular crisis situation in a municipal organization, this thesis investigates how public organizations organize to collect and share information with the use of social media during crisis events. The results show that social media enabled fast response to citizens, due to the coordination and collaboration ability within the municipality. The importance of an existing digital strategy is recognized, for proper managing of social media as response to sudden change.