2020 Atlantic hurricanes - Extreme of extremes

Atlantic hurricanes 2020 – Extreme of extremes

The 2020 Atlantic hurricane season had the most named storms (30) of which the highest number (12) made landfall and the most storms to form in September (10). 2020 was the 5th successive year with above average hurricane activity.

On 14 September 2020, six named storms were formed concurrently.

A significant feature was the explosive intensification by up to 80km/h in 24h. This has been the case for the past few decades. There has also been a reduction in the speed of forward movement.

In Central America, never before had two intense hurricanes (Eta and Iota) hit the same area with such strength in rapid succession.

Storm development were due to several favourable environmental factors. The sea was abnormally warm at the beginning of the season.

By August, a very active monsoon pattern developed over North Western Africa helped to produce strong atmospheric waves that can develop into storms. A moderate to strong La Niña helped to reduce the wind shear that can hinder hurricane formation and intensification.

Local atmospheric and oceanic conditions such as weak easterly trade winds prevented upwelling in the Caribbean, allowing a deep pool of extremely warm water to develop. This provided potent fuel for rapidly intensifying storms like Eta and Iota.

Though warming seas may heighten hurricane activity in the future, the abundance of storms this year is not itself a signal of future storm trends. There is no observed global trend on the frequency of storms.

(Extracts from Kasha Patel, NOAA).