Once in a century floods could become a yearly event: Study

Historically rare flooding may become an annual phenomenon
Extreme floods would impact coastal cities first, as soon as 2040
A proactive approach to urban development could help avoid disaster

Updated: Oct 2, 2023 / 01:30 PM CDT

Rescue workers with Tidewater Disaster Response wade through a tidal surge on SW 358 Highway while looking for people in need of help after the Steinhatchee River flooded on Wednesday, Aug 30, 2023, in Steinhatchee, Fla., following the arrival of Hurricane Idalia. (Douglas R. Clifford/Tampa Bay Times via AP)

(NewsNation) — Extreme flooding considered to be so rare it only happens once every 100 years could become an annual occurrence by the end of this century, according to a study published by the American Geophysical Union.

Coastal communities — where rising sea levels could impact flooding with storms and tides — could feel the impact first in 2040. By 2050, researchers say the impact will be felt in communities worldwide.

“The threshold that we expect to be exceeded once every hundred years on average is going to be exceeded much more frequently in a warmer climate until they are no longer considered 100-year events,” said Hamed Moftakhari, a civil engineer and professor at the University of Alabama who supervised the project.

According to the study, a 100-year flood is an extreme water level that has a 1% chance of being exceeded in any given year and is based on historical data.

Researchers analyzed flood data based on changing weather patterns from the International Panel on Climate Change, saying even if carbon dioxide emissions peak in 2040 (a more moderate projection than others offered by the panel), these kinds of floods will still occur.

A proactive approach to land planning, urban development and coastal protective measures could help communities reduce flooding and avoid disaster, Moftakhari said.