Social media has profound impact on society and affects many aspects of human life. Its applications in combating crises are unanticipated results of social media inventors and many lessons could be learned from its applications in combating real crises. From July 2011 to January 2012, Thailand experienced a 7-month flood disaster and more than 13.6 million people were affected. Hundreds of social communities in Thailand thrived to help prepare, combat, mitigate, and respond to this crisis. This paper offers a structuration perspective to examine knowledge-sharing activities employed by these local social communities to combat the crisis. Interviews were conducted with social community leaders, victims, and government officers to reflect actions taken before, during and after the disaster. Based on the structuration theory and rich data collected from key participants in this crisis event, a social media-based crisis management framework is proposed. The analysis results suggest that social media should be utilized to help a society thrive in crises by managing community-based knowledge and creating chaotic order. The findings of this study could guide crisis managers into turning each crisis into opportunity with the creative use of social media as a knowledge-sharing tool.