Large infrastructure projects can often cause disruptions with those outside the immediate project area experiencing negative effects. Twitter (now X) and its ensuing online firestorms are ways these project community make themselves heard and influence the project and its societal outcome. Using the case study of the High Speed Two large infrastructure project in the U.K., this article retrieves over 950 000 tweets regarding the project from 2013 to 2019, and using dynamic topic modeling classifies 10 instances of online firestorms over this period covering environmental impacts, legislative dynamics, budget of the project, performance of the project, etc. We then theorize how online firestorms are practiced in large infrastructure projects, discussing the different topics considered in them, their sociomateriality, their difficulty in sustaining, how they can be recreated with similar new issues, how it is used as a persuasive tool, how they can change the project, and how they can be used for risk management. The findings help project managers by enabling them to understand social risks in projects and take proactive steps in addressing them.