Purpose - Nowadays, natural disasters happen increasingly and create severe damage worldwide. Being prepared and responsive is of great necessity. Therefore, this study aimed to analyze the capacity and efficiency of the public sector in disaster management, especially regarding online media. Design/methodology/approach - The National Disaster Warning Centre (NDWC) in Thailand was the online media selected as a case study. The website was measured by criteria of the W3C (World Wide Web Consortium). The concept of content analysis was used to analyze the information on Twitterand Facebook during the worst flooding ever in Thailand during October, 2011. Findings - The online media in this study could be considered as a critical and useful tool for developing disaster management. However, the website concerned could not achieve the W3C standard, and Twitter could not interest people in society, due to its content. This fact is confirmed by Twitter having only 11,142 followers, while another NGO; #Thaiflood, had 107,680. Facebook faced the same problem as Twitter of drawing little attention or interaction from society. Practical implications - There are large gapsin the development of online media in the public sector. All media should be improved to meet the required standard, and be considered a reliable source for disaster management. Originality/value - Most e-government in Thailand, for example e-disaster, lacks evaluation of its capacity. This study provides and suggests insightful information for development. If the media could be improved, preparation for disaster would be better, and responses to it prompt.