Estimating excess migration associated with tropical storms in the USA 1990–2010

Tropical storms are among the most devastating natural disasters in the USA. Climate change is projected to make them even more destructive, and the number of people and properties at risk has steadily increased over the past several decades. Migration is often seen by scholars as an adaptation strategy to reduce exposure to future natural disasters. However, studies of migration after tropical storms have led to inconsistent results and have not analyzed post-storm migration from the viewpoint of exposure to future events. This paper adopts an innovative approach to estimate “excess migration” associated with tropical storms using Bayesian hierarchical models, and decomposes migration by risk of exposure to natural disasters of the origin and destination to understand whether migrants move to safer areas or rather riskier ones. Findings indicate that excess migration after tropical storms is rare and generally fails to reduce the number of people at risk of experiencing future natural disasters. Only the most destructive tropical storms are associated with significant excess migration. Finally, findings further suggest that neither the amount of post-disaster assistance nor the socio-demographic characteristics of the affected counties are strongly associated with excess migration.