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.

热带风暴是美国最具破坏性的自然灾害之一。预计气候变化将使其更具破坏性，过去几十年来，面临风险的人员和财产数量稳步增加。学者们经常将移民视为减少未来自然灾害风险的一种适应策略。然而，对热带风暴后迁移的研究导致了不一致的结果，并且没有从暴露于未来事件的角度来分析风暴后迁移。本文采用创新方法，利用贝叶斯分层模型来估计与热带风暴相关的“过度移民”，并根据来源地和目的地遭受自然灾害的风险对移民进行分解，以了解移民是迁移到更安全的地区还是风险更高的地区。研究结果表明，热带风暴过后的过度移民很少见，而且通常无法减少面临未来自然灾害风险的人数。只有最具破坏性的热带风暴才会导致大量过度迁徙。最后，研究结果进一步表明，灾后援助的数额和受影响县的社会人口特征都与过度移民没有密切关系。