To Understand Hurricanes of the Future, USGS Looks for Answers in Sand

Sand core — Sediment core showing storm deposits. This example of a core was collected from the Dominican Republic. (File image courtesy Kristen Steele, USGS)

To get a better perspective on the storms of the future, the U.S. Geological Survey is studying evidence of past hurricanes in buried sediments in the Florida Panhandle.

Hundreds of years ago, local climate conditions in the Gulf of Mexico were similar to what they are now - and what they likely will be in a few decades. USGS scientists believe that the signs of past storms from this time period can help extend the historical record of extreme weather in the region, improving modeling and predictions of future storm activity as the climate warms again.

The data suggests that the existing records of storms - which date back only to the mid-1800s - may not fully capture the risk of high-powered hurricanes during warm periods in the local climate.

“Most existing records on hurricanes that are used to help forecast storms date back to 1851, which is just over 170 years ago, and our research is looking beyond that by several thousands of years,” said USGS research geologist Jessica Rodysill. “We are collecting sediment from below the Earth’s surface and analyzing those samples to learn about hurricane occurrence over a long period.”

Specifically, the team collected sediment samples from two sites in coastal Florida, a bit inland from the shore. The soil at these sites is mostly fine sediment, punctuated by periodic layers of sand deposits. The sand represents incidents of heavy flooding from the arrival of a hurricane. The age, type, quantity and thickness of the sand deposit gives clues about the intensity of the storm.

Based on the geological record, the odds of a major storm may be higher during periods when the local climate is warmer. The evidence in the cores suggests that there were several previously unknown Category 4-5 hurricanes during a period from 800-1,400 years ago, when sea surface temperatures were higher in parts of the Gulf of Mexico and the Atlantic. Before the study, the only known Category 4 or 5 hurricane to ever make landfall in the area was Hurricane Michael, which struck Panama City in 2018.

Computerized climate models predict that hurricane activity could increase in the Gulf of Mexico as ocean temperatures warm in the decade ahead, and USGS believes that the new study supports this prediction - though other physical oceanographic factors will also play a role.