論文アブストラクト：Using the 2014 Carlton Complex Wildfire as a case study, we examine who contributes official information online during a crisis event, and the timeliness and relevance of the information provided. We identify and describe the communication behaviors of four types of official information sources (Event Based Resources, Local Responders, Local News Media, and Cooperating Agencies), and collect message data from each source's website, public Facebook page, and/or Twitter account. The data show that the Local News Media provided the highest quantity of relevant information and the timeliest information. Event Based Resources shared the highest percentage of relevant information, however, it was often unclear who managed these resources and the credibility of the information. Based on these findings, we offer suggestions for how providers of official crisis information might better manage their online communications and ways that the public can find more timely and relevant online crisis information from official sources.