Abstract: As one of the most well-known social media platforms in China, Weibo provides an online public sphere. During the 2018 Shouguang flood, many people who were affected converged on the platform to discuss the disaster. The government ? the highest emergency management authority ? was accused of using censorship and other measures to suppress the coverage of the disaster. Based on an analysis of 34 qualitative interviews with Weibo users, of which nine directly address the Shouguang floods, this paper examines how three major actors contested facts and responsibilities during the disaster. Focusing on the state-censored, market-moderated social media context in China, our ongoing study provides new insights into a universal challenge of managing diverging interpretations and expectations in risk communication. We show that the establishing and framing of facts is inherently ethical and political. Time, time-space compression, liability and scales of risk responsibility emerge as critical points of friction. We draw on theories of risk governance, public discourse, computer supported collaborative work, and media studies for analysis and to articulate avenues for design.