Tropical cyclones act as 'massive heat pumps' that fuel extreme heat

The National Weather Service issued an extreme heat advisory three days after Hurricane Fiona hit Puerto Rico.

According to a new University of Arizona-led study, above-average temperatures almost always follow tropical storms and hurricanes, and may soar to nearly 10 degrees hotter than average. The study's authors stressed that their results are likely conservative estimates of how high temperatures can go after a storm.

Tropical storms can cause damage from strong winds, storm surge, intense rain and flooding, but they can also cause extreme heat. In areas that weren't directly impacted by the storm, above-average temperatures can happen days later.

Disaster recovery can be complicated by multiple extreme events happening within a short period of time. Medical providers are concerned about heat. Our results show that public information about heat risk should be included in tropical cyclone preparation.

Between 1991 and 2020 there were 53 tropical storms in the eastern Caribbean and 205 interactions between them. After the storm, the heat index values in the cities were always higher than average.

"Everyone's focus is on the destructive power of tropical storms and hurricanes, but our focus is on the combined hazard of storm and heat," he said.

Massive heat pumps, redistributing heat for a large spatial distance around the center of the storm, and they leave massive destruction in their wake that can knock out the energy grid are some of the characteristics of hurricanes. That combination is dangerous because it slows recovery.

The authors think that high heat index values will increase in the future because of climate change.

The climate change impacts are easy to understand. There will be more people in harm's way as hurricanes drop more intense rain. If you drape on top of that hotter environment, you will get a bigger impact.

The Arizona Initiative for Resilience and Development supports UArizona research in regions most sensitive to social and environmental changes as well as research on topics that advance sustainable development.

There is a larger effort to build climate resilience in Puerto Rico. The workshops the researchers held with public health researchers and metrological service professionals in the Caribbean pointed to the need to better understand the impact of heat.

This is a new hazard and we want to call attention to it. The work we did with the National Weather Service in Puerto Rico was not discussed in the paper. There is a heat awareness week in Puerto Rico from May 11 to 15.

Other members of the research team include Simon Mason from Columbia University's International Research Institute for Climate and Society and Teddy Allen from the Caribbean Institute for Meteorology and Hydrology.

There is more information about hurricanes and anomalous heat in the Caribbean. There is a book titled "1029/2022GL099740."

Journal information: Geophysical Research Letters