By contrast, the two most recent wet periods had an average of 5.52 and 8.53 days a year with intense hurricanes.

Less well developed is the ability to predict how intense a hurricane will be.

It remained an intense hurricane for nearly eight days, an unusual occurrence.

However, shortly after, the eye became much better defined and developed several mesovortices, a feature typical of intense hurricanes.

The combined tropical cyclone subsequently became a very intense hurricane on September 19.

Although the record shows a distinct increase in the number and strength of intense hurricanes, therefore, experts regard the early data as suspect.

The storm was described as one of the most intense hurricanes in Jamaica's recorded history.

He concluded that "this was probably the most intense hurricane in New England history."

Almost every intense hurricane undergoes at least one of these cycles during its existence.

"Warm sea-surface temperatures are clearly the fuel for intense hurricanes," he said.