The Atlantic hurricane season, which normally runs from June through the end of November, has broken a record for going the longest without producing a single hurricane in more than a century.
Forecasters have tied the unusually quiet stretch to a strong El Nino event in the Pacific Ocean. El Nino is a periodic warming of surface waters in the eastern and central Pacific that shifts weather patterns worldwide, and one of its well-documented effects on the Atlantic is an increase in high-altitude wind shear, winds that blow at different speeds or directions at different heights. That shear tends to tear apart the rotating structure that developing tropical storms need to strengthen into hurricanes.
For residents of the Gulf Coast, the Southeast, and the Caribbean, a quiet hurricane season generally means fewer evacuation orders, less storm damage, and lower insurance losses for the year, all of which matter to regional economies that depend heavily on tourism and coastal property.
Meteorologists have nonetheless cautioned that the season is not over until it officially closes at the end of November, and that a quiet stretch can end abruptly if atmospheric conditions shift. Some of the most damaging Atlantic storms in past decades have formed later in the season, in October or even November, so forecasters are continuing to monitor conditions rather than declaring the season closed.
Forecasters will be watching whether the El Nino pattern holds through the final weeks of hurricane season, since any weakening could allow storm activity to pick up before the season ends.
Why does El Nino calm the Atlantic hurricane season?
El Nino tends to increase high-altitude wind shear over the Atlantic, and that shear disrupts the rotating structure storms need to strengthen into hurricanes.
Is hurricane season over?
No. The season runs through the end of November, and forecasters caution that conditions can still shift before then.