Why are some Atlantic hurricane seasons more active than others?

For any given season, multiple ocean and atmospheric conditions, such as El Nino or La Nina, influence whether Atlantic storms develop, how big they get and how long they last. Since 1995, we have been experiencing what scientists refer to as an active or high-activity era for Atlantic hurricane seasons — a natural, cyclical phenomenon.

How did we get here?

Scientific studies point to the Atlantic Multi-decadal Oscillation (AMO) as the most prominent link to the active era we are in.

The AMO cycle swings between extended periods, typically lasting 20-40 years, of warm and cool phases in North Atlantic Ocean temperatures. The atmospheric conditions that make way for the AMO warm phase can create the perfect storm and heighten Atlantic hurricane activity and storm strength. These conditions include:

 

 

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Image via NOAA.