In this article, the author theorizes the process that a World Health Organization work group used to update yellow fever risk maps published in the Yellow Book, a handbook created by the Centers for Disease Control and Prevention for international travelers, from a “wicked problems” perspective. She argues that using this model highlights the complexity of nonexperts’ risk assessment practices in this context and that the work group's decision to create vaccination maps demonstrates an increased awareness of the embodied decision-making practices that nonexperts perform, aligning with and contributing to the growing emphasis on creating user-centered risk information that can be seen in some risk communication.