With some scientists saying global warming is causing an increasing frequency and strength of hurricanes, there is a call for a new category of storms.

In fact, ABC News says there have already been hurricanes strong enough to qualify as Category 6 -- having sustained winds of more than 175 or 180 mph.

The current scale defines storms with sustained winds between 74 and 95 mph as Category 1 hurricanes, Category 2 has sustained winds from 96 to 110 mph, Category 3 has sustained winds from 111 to 130 mph, Category 4 has sustained winds between 131 and 155 mph, and a Category 5 storm has sustained winds greater than 155 mph.

A Category 6 storm would have wind speeds greater than 175 or 180 mph.

U.S. government forecasters at the National Hurricane Forecast Center in Miami didn't well predict the 2005 Atlantic hurricane season, partly because of their unfamiliarity with global warming.

In May 2005, NOAA predicted the Atlantic would see 12 to 15 named tropical storms. There were 28. The experts forecast seven to nine storms would become hurricanes but 15 reached that level.

Copyright 2006 by United Press International