Strengthening tropical cyclones are associated with more frequent hazardous material pipeline failures in the Eastern US.

Over 30,000 hazardous material pipeline (HMP) failures have caused nearly $11 billion in damages since 1970. Tropical cyclones, which cause more infrastructure damage than all other forms of natural disasters combined, are thought to be under-attributed causes of HMP failures, largely due to historic policy around pipeline failure reporting. This study defines tropical cyclone-associated HMP failure frequency based on spatiotemporal concomitance, while detrending for background HMP failure rates, and explores the relationship between the likelihood and frequency of HMP failures and tropical cyclone intensity using a method that accounts for omitted variable bias associated with unparameterized storm and pipeline characteristics. Though only 4.3% of HMP failures have been formally linked to natural forcings, 32.5% of HMP failures in the eastern United States occur within 60 days of a tropical cyclone. HMP failures 60 days after a tropical cyclone intersection are both significantly more likely, and exponentially more frequent, with increasing tropical cyclone intensity. Since 1975, the annual frequency of tropical cyclone-associated pipeline failures has increased by an order of magnitude. During this same period, the annual lifetime maximum intensity of a tropical cyclone intersecting with HMP infrastructure has increased from a Category 3 to a Category 4 storm on the Saffir-Simpson hurricane scale. Implications for pipeline design, and of accurate natural hazards-related cause attribution on HMP failure incident reports, are discussed.