Should we fear a hurricane season that will still be abnormally intense this year?

Each year, near the seasonseason hurricanes, it’s the same speech: the hurricane forecast bulletins announce each time a more active season than normal. Except this year. NOAA and the various American universities, which publish bulletins concerning the hurricane season in the North Atlantic, all announce a season “close to normal”, or even “below normal”! In the current context of global warming, these statements may come as a surprise: rising ocean temperatures are the main fuel for hurricanes. When the waters are abnormally warm, cyclonic phenomena form more easily, and above all, intensify more quickly.

A return to normal expected in 2023

There NOAANOAAAmerican organization of reference for the study of the oceans and theatmosphereatmosphere, estimates that the North Atlantic hurricane season is 40% likely to be normal, 30% weaker than normal, and 30% above normal. Between June 1 and November 30, NOAA predicts 12 to 17 phenomena, including 5 to 9 hurricanes, including 1 to 4 major hurricanes. Of course, this does not necessarily mean that they will hit the ground and do damage. The confidence index for all these forecasts is 70%. 16 hurricane phenomena formed in the North Atlantic in 2022, 21 in 2021 and 31 in 2020, a record. In any case, the 2023 hurricane season is forecast to be “less active than those of previous years”: it will therefore probably be a return to normal after a succession of abnormally intense seasons.

The return of El Niño will disrupt the formation of hurricanes

So what’s going on this year? Main factor that will influence the 2023 season, the return of El Niño, a warming of part of the waters of the Pacific which has an influence on the global climate (after 3 years of La NinaLa Nina, its cold counterpart). El Niño is well known for decreasing North Atlantic hurricane activity, while La Niña often has the effect of making it more intense. El Niño impacts the weather reportweather report of the world in different ways depending on the region: in the Atlantic Ocean, it causes a zone of high pressurespressures in the atmosphere, with windswinds strong at high altitudes. This strong wind shear prevents hurricanes from rising in altitude, and therefore from becoming more powerful: in these conditions, hurricanes therefore have more difficulty in forming, and are therefore less intense.

However, the worrying warming of ocean waters could change the situation: climate change complicates hurricane forecasting by disrupting the natural laws of the atmosphere and the oceans. The NOAA reminds us, even if the hurricane season is really less intense than the previous ones, it only takes one hurricane to create a large-scale disaster. Like Hurricane Ian, which marked the 2022 hurricane season: it devastated Florida in September, killing at least 161 people and tens of billions of dollars in damage.