Why do hurricanes have different categories?

Answer 1

Tropical systems that form in the Atlantic and East Pacific are classified on a scale that describes the intensity of the storm. This scale is called the Saffir-Simpson scale, which ranks storms that reach at least hurricane force (with sustained winds of 74 mph or greater) on a scale from one to five. This scale is based on the sustained windspeed within the storm. Beginning with the Cat 1 storms, we can use this scale to determine the amount of destruction that will be caused whenever the storm makes it's landfall. While the storms are measured by their windspeed, meteorologists also make note of the barometric pressure of the storm. By keeping this information updated, the National Hurricane Center issues advisories that keep the public alert on the danger. The strongest of the scale, Cat 5, will have sustained winds of 156mph or greater. In 2005, Hurricane Wilma blew it's way into the record books becoming one of the strongest hurricanes ever in the Atlantic Basin. It had the lowest central pressure ever recorded in the Atlantic Basin, reaching an estimated minimum pressure of 882 mb at its peak intensity. This was an absolutely devastating storm, with maximum sustained winds estimated to have exceeded 160 kts. I say estimated because the reading of 882 mb was the last taken by an air force reconnaissance aircraft at the time - in all actuality the pressure could have been quite a bit lower, but the fury of the storm prevented further accurate pressure readings. During it's peak intensity, Wilma had an eye that was a mere 2 nautical miles across - which is the smallest eye of any recorded storm in the NHC archives. To review the full description of each category, with the descriptions of the type of damage to be expected from such a storm, can be found at www.nhc.noaa.gov/aboutsshs.shtml. Overall - the storms are categorized to provide local governments with an idea of what the storm will cause upon impact - thus allowing the efficient movement of resources, ensuring that after the storm has passed, there can be effective action to correct and resolve any storm related issues.

Answer 2

Hurricanes are ranked into categories largely to provide an estimate of the damage the storm might cause.