Spain experienced an extreme weather event known as DANA (Cut-off Low) between late October and early November 2024. This event triggered intense rainfall, causing several rivers to overflow and severely damaging infrastructure. The Valencian Community, with over 200 fatalities, was among the most affected regions in what is considered one of the most severe hydrological disasters in the country’s contemporary history. This research aimed to understand how digital environments facilitated the organization and mobilization of citizens in response to institutional inaction during this crisis. The study’s primary objective was to analyze public reactions on social media, specifically on X, in light of the lack of effective intervention by authorities. A mixed-methods approach achieved this by combining a review of official documents and media reports with an analysis of social media posts. The main conclusion drawn from this study is that social media interactions during this emergency fostered emotional, social, and organizational bonds in the initial days of the crisis. These connections aimed to safeguard citizens’ well-being through the aid offered by individual platform users as part of spontaneous collective action.