It is unusual to see three storms forming at once this late in the season, meteorologist Philip Klotzbach of Colorado State University pointed out on X, formerly known as Twitter. In fact, it is the first time this number of hurricanes has been seen simultaneously across the Atlantic in the month of October since satellite records began in 1966.

"It likely was a reflection of both extremely warm waters, as well as low levels of vertical wind shear [the change in wind direction and speed with height in the atmosphere]," says Klotzbach, pointing to near-record Atlantic temperatures.