In a public health crisis, experts (such as epidemiologists, public health officers, physicians and virologists) support key decision makers with advice in a highly dynamic, pressured, and time-sensitive context. Experts must process information (to provide advice) as quickly as possible, yet this must be balanced with ensuring the information is credible, reliable, and relevant. When an unexpected event occurs, it may lead to a gap between what is experienced and what was expected; sensemaking is a meaning creation process which is engaged to fill the gap. This research explores how experts engage in sensemaking during a public health crisis.