In a Warming Atlantic, Hurricanes Increasingly Arrive in Groups

As ocean waters heat up, the Atlantic is increasingly seeing not just one, but two or more hurricanes spin up at the same time. That is the finding of a new study, which warns that warming is raising the risk that coastal cities may be battered by back-to-back storms. 

In September 2017, hurricanes Katia, Irma, and Jose haunted the Atlantic at the same time. In September 2020, the Atlantic saw a total of 10 named storms, the most of any month on record, with five of those — Sally, Paulette, Rene, Teddy, and Vicki — appearing simultaneously. 

With warming, some years are seeing an unusually large number of hurricanes, raising the likelihood that two or more appear at the same time. But a growing number of storms cannot fully explain why hurricanes are now so often appearing in groups. The new study, published in Nature Climate Change, concluded that Atlantic warming is actually setting the conditions for multiple hurricanes to arise all at once.

The result, scientists say, is that while the Northwest Pacific has historically seen the most hurricane clusters, the Atlantic is now a growing hotspot. The odds that clusters in the Atlantic outnumber those in the Northwest Pacific in any given year have grown tenfold over the past half-century.

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