Critical climate stress moments may be defined as those moments when households, communities, and their livelihood systems are vulnerable to climate related risks and hazards. This working paper examines critical climate stress moments due to specific climatic and biophysical causes experienced by the people in the Teesta River basin in India and Bangladesh. The Teesta, like other river basins of the Himalaya, has a fragile geology, as well as complex climate, ecosystems and socio-economic conditions. Critical moments can serve as a tool for communicating vulnerabilities and the challenges to sustainable lives and livelihoods, and to link vulnerability assessments with adaptation policy and action.