In the past crisis sensemaking activities have primarily been controlled by professional emergency responders and the media. Social media, however, has the potential to see a shift towards more grassroots and ad hoc citizen engagement. This paper sets out our vision and our progress in implementation of a new online platform called ‘Majority Report’, which aims to empower citizen sensemaking activities around crisis events. The concept is to facilitate citizen volunteers to draw together a range of digital media (photographs, Tweets, videos, etc.) to present stories of crisis events, and thus demarcate arguments about different understandings in terms of the temporal ordering of event narrative components and their relations to each other. Through collaborative usages of the platform, accounts may be improved by others, and variants may be presented and compared to challenge existing assumptions and beliefs.