Dazbo, it happens, and nobody is sure why. Some years there are more than others , and there are apparent* short term cycles in annual Hurricane numbers ( 40-60 years IIRC) I can't remember if these cycles show up in other tropical strom zones, implying a worldwide effect, or are limited to the North Atlantic.

Climatic changes associated with elevated CO2 should increase either hurricane intensity or frequency, or both. Another predicted effect is tropical stroms developing in the Southern Atlantic, and heading for Brazil, which was seen for the first time last year.

It's all just heat moving from the Equator, where it's absorbed to the Poles, where it escapes. Increased CO2, more heat retained, more energy in the system to be moved, so more energy to feed strorms etc.


* acedemic term, meaning gives us a decade, and some reaserch grants for a couple of teams in various places, and we might be able to tell you.