Mortality caused by tropical cyclones in the United States

Natural disasters trigger complex chains of events within human societies¹. Immediate deaths and damage are directly observed after a disaster and are widely studied, but delayed downstream outcomes, indirectly caused by the disaster, are difficult to trace back to the initial event^1,2. Tropical cyclones (TCs)-that is, hurricanes and tropical storms-are widespread globally and have lasting economic impacts^3-5, but their full health impact remains unknown. Here we conduct a large-scale evaluation of long-term effects of TCs on human mortality in the contiguous United States (CONUS) for all TCs between 1930 and 2015. We observe a robust increase in excess mortality that persists for 15 years after each geophysical event. We estimate that the average TC generates 7,000-11,000 excess deaths, exceeding the average of 24 immediate deaths reported in government statistics^6,7. Tracking the effects of 501 historical storms, we compute that the TC climate of CONUS imposes an undocumented mortality burden that explains a substantial fraction of the higher mortality rates along the Atlantic coast and is equal to roughly 3.2-5.1% of all deaths. These findings suggest that the TC climate, previously thought to be unimportant for broader public health outcomes, is a meaningful underlying driver for the distribution of mortality risk in CONUS, especially among infants (less than 1 year of age), people 1-44 years of age, and the Black population. Understanding why TCs induce this excess mortality is likely to yield substantial health benefits.