The term Hurricane is a classification of intensity of a topical cyclone. In order to be considered a hurricane a storm must have maximum sustained winds of at least 74 mph.
No, Hurricane Opal was not the strongest hurricane by any means. Opal was a strong category 4 with 150 mph winds. The strongest hurricane on record was Hurricane Camille with winds of 190-200 mph.
Katrina was stronger. At peak intensity Hurricane Katrina had 175 mph sustained winds and a central pressure of 902 millibars (the lower the pressure, the stronger the hurricane). By comparison,...
There are hundreds of unnamed hurricanes in each basin. You're going to have to be more specific with what year you are looking for and even then, what month and day was the storm active