The unfortunate mix between storm surge and heavy rainfall may put at serious risk large areas of the U.S. coast including cities, new study suggests.
The phenomenon called compound flooding become more common in the 1950s but the rising sea levels made it even worse especially in the U.S. where about 40 percent of the population is cramped in the coastal areas.
Thomas Wahl from the University of South Florida and lead author of the study along with his fellow researchers looked for a link between storm surge and heavy rainfall. They sifted through the records on storm surge on all U.S. coasts.
The team found an interesting link between the two phenomena on large stretches of coast of the Gulf and Atlantic. Plus, researchers noticed that coastal flooding was more common nowadays than in the past.
Wahl noted that people tend to ignore such links and are often caught off guard. He also said that the new study, which was published Monday in the journal Nature Climate Change, was designed to raise awareness on the existence of those events and their risks.
Scientists explained that the sea water brought to the land by raging storms such as hurricanes can join forces with heavy rains and boost the magnitude of coastal flooding in unprecedented ways.
Usually, the two events reinforce one another. The inland rains can boost storm-driven flooding, or the latter can increase water levels which can reach streets and people’s homes due to gravitation.
During their study, researchers also wanted to learn how the relationship between storm surge and rainfall looked like on a historical level. The data revealed that compound flooding events became more severe after the first half of the last century in most locations along the U.S. coastal area.
Scientists speculate that that may have something to do with either global warming or natural events such as El Niño, which naturally and cyclically reoccurs in definite locations. The team couldn’t tell whether compound flooding would get worse over time.
“It might be stable now, it might continue to increase, it might go down,”
As a follow-up, the team plans to assess future risks of the phenomenon and try to predict how the trend may look like in the following decades. The study authors acknowledged that their research was barely a “starting point,” but they hope that the findings may help municipalities and coastal county authorities prevent and better tackle coastal floods.
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