How is the development of knowledge in communities affected by disaster events? We present a state-of-the-art tool that provides the ability to compare discourses in communities, by converting text messages to communication graphs and enabling graph comparison visualization. The tool’s validation includes conversion of chats from 81 WhatsApp groups to graphs and comparison between them, after divided to time-periods around a global crisis. Results indicate that (1) density is reduced during crises, meaning that communication decreases, (2) There is no change in network influencers between periods of times during the crisis, (3) there is a direct effect of the nature of a time-period on the nature of discourse in the community and (4) The suggested tool is suitable for communication graph comparison. The contribution of the current research is a novel approach to measure and compare knowledge development in communities using a graph comparison tool. This study represents a progress in understanding the differences in communication during different times of crises in communities. Implications of the research relate to mechanism for communication comparison including visualization and analysis. The ability to identify communication patterns in communities assists in understanding the development of collective knowledge.