Scientific advice has an important role to play in all phases of the crisis management cycle: preparedness, response and recovery. It can be particularly valuable when a crisis occurs and develops, which is when sense-making matters. However, this value is dependent on the quality and timeliness of the advice and, most importantly, its relevance to the decisions that crisis managers and policymakers have to make. Generating rigorous scientific advice requires access to relevant data, information and expertise. Ensuring that this advice is useful requires effective connections between scientific advisory processes and crisis management mechanisms. When crises are novel, complex or large in scale and, in particular, when they have a trans-national impact, ensuring the rigour and usefulness of scientific advice can be particularly challenging. It requires effective mechanisms for rapid exchange of data and information and a common understanding of how scientific advisory mechanisms operate in different countries. Otherwise, there is a serious risk of confusion that can impede the crisis response, undermine public trust in government and responsible agencies, and, ultimately, lead to avoidable loss of life and increased economic disruption.