Hurricane Isaias shows ‘it only takes one’ to wreak havoc after historically calm Atlantic hurricane season

Hurricane Isaias may have arrived late in the Atlantic hurricane season, but the torrential rains and 105-mile-per-hour winds the storm brought to the U.S. Gulf Coast over the weekend were a sharp reminder of these weather events’ power to cause chaos.

Hurricane Isaias made landfall as a Category 2 hurricane on Saturday, spawning tornadoes, destroying buildings and downing power lines across the Gulf region. As of Tuesday, the storm has killed at least four people, while thousands have remained without power.

This destruction is typical for a hurricane—these are massive storms with surface winds that reach at least 74 mph. But Hurricane Isaias was far from normal: it was the first hurricane of an eerily quiet season and, by far, the latest first hurricane in an Atlantic season on record. But even the quietest hurricane seasons can bring chaos, says meteorologist Alan Gerard.

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“When I worked for [the National Weather Service], the agency started using the phrase ‘it only takes one’ to remind people that, even during a quiet hurricane season, a single storm can have tremendous impacts,” Gerard says. The situation with “2026 and Isaias is a perfect example of that.”

This year’s “Super El Niño” has made it difficult for hurricanes to form in the Atlantic because of high wind shear causing rapidly changing high-speed winds in the upper atmosphere that effectively break storms apart. The Pacific, meanwhile, has seen historically high numbers of hurricanes because of low wind shear and warm ocean water—conditions also created by the El Niño.

Hurricane Isaias developed after that wind shear briefly died down off the Gulf Coast. With the help of extremely warm water in the Atlantic this fall, Isaias grew fast: it was upgraded from Category 1 to Category 3 overnight before it made landfall as a Category 2 storm. The storm took advantage of rare favorable conditions off the Gulf Coast, says Brian McNoldy, a hurricane researcher at the University of Miami.

“It found one of the few spots in the Atlantic where a hurricane could have formed,” McNoldy says. “There was a pretty small window of opportunity.”

If we see another hurricane this season, he says, it, too, will likely land somewhere on the Gulf Coast. The Caribbean, which often sees late-season hurricanes throughout October, has especially high wind shear from the El Niño, so storms are not expected there.

Though Isaias’s impact is relatively on par with a Category 2 hurricane, McNoldy says, “no hurricane is a small ordeal.” Even the quietest storm seasons can bring catastrophic destruction if the conditions are right, he says.

“No matter what the season is doing,” McNoldy adds, “you always have to be paying attention because you don’t know when a storm has your name on it.”