Warmer climate could reshape hurricane risk, its relationship with El Niño around Hawaiʻi

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A new study examining how tropical cyclone activity near Hawai'i could change in a warmer future finds a shift toward stronger storms, even though uncertainty remains about whether the total number of storms near the islands will increase. The study was led by researchers at the University of Hawai'i at Mānoa School of Ocean and Earth Science and Technology (SOEST).

"This research addresses a hazard that is rare in Hawai'i but can have enormous consequences when it occurs," said Nicole Murray, lead author who was a postdoctoral researcher in the SOEST Department of Atmospheric Sciences at the time of this research. "The events of this hurricane season make that especially tangible: storms do not need to make a conventional landfall to disrupt communities, damage infrastructure and create dangerous flooding and wind impacts."

Only a small number of tropical cyclones have directly affected the islands during the modern observational record. Limited data, however, makes it difficult for scientists to estimate the probabilities of rare events or determine how those probabilities might change in the future.

Simulating tropical cyclones

Murray and team addressed that problem by using the Columbia Tropical Cyclone Hazard computer model created by study co-authors Chia-Ying Lee and Suzana Camargo at Columbia University. The model generated thousands of years' worth of synthetic tropical cyclones from the atmospheric and oceanic conditions simulated by seven global climate models. This provided the researchers with a much larger sample of possible storms than observations alone could provide.

They examined storms passing within 300 nautical miles of Hawai'i and analyzed their frequency, intensity, tracks, duration, speed and landfalls under historical, mid-century and late-century climates. The future simulations use a high-emissions scenario to examine how tropical cyclone activity could respond under substantial future warming. They also separated storms occurring during El Niño and La Niña years, allowing the team to examine whether the relationship between El Niño-Southern Oscillation and Hawai'i tropical cyclone hazard could change in a warmer future.

Assessing changes in El Niño and hurricane hazard

El Niño has historically provided useful context for understanding heightened tropical cyclone hazards around Hawai'i. This study found an important change in the relationship between El Niño and Hawai'i's tropical cyclone risk. Historically, El Niño tends to favor stronger and more frequent tropical cyclones near Hawai'i compared with La Niña. In the team's late-century simulations, the differences between El Niño and La Niña become less pronounced, particularly for tropical cyclone wind hazard, while the spatial pattern of storm tracks also changes. During El Niño, tropical cyclone tracks shift southwest of the Hawaiian Islands relative to La Niña conditions.

"The 2026 hurricane season has provided a powerful reminder of this," said Christina Karamperidou, co-author and SOEST atmospheric sciences professor. "Hurricane Lala passed just south of the islands in August and produced severe flooding and damaging winds across Hawai'i; Hurricane Lowell approached Hawai'i from the south in September before passing west of the state, producing damaging winds, heavy rainfall and flooding, with particularly severe impacts on Kaua'i."

This research connects large-scale climate dynamics of the tropical Pacific with hazards that impact communities across Hawai'i. Tropical cyclone risk is not simply a question of how many hurricanes make landfall. Storms passing near the islands can produce damaging winds, extreme rainfall, flooding, landslides, high surf and other cascading hazards.