Hurricane Categories

“Hurricane Categories: An Overview”

Humans have always had much-deserved respect and fear for hurricanes – and rightly so. Throughout our history there have been a number of devastating hurricanes that have ravaged communities, vast landscapes, and lead to the deaths of countless individuals. With improvements in technology, bringing with it satellite imagery, computer simulations and a wealth of data, researchers in meteorology and those in organizations like the National Hurricane Center (NHC) have greatly expanded the ability for populations in affected areas to be forewarned of oncoming hurricane activity. 

Prior to 1972, the NHC was able to disseminate some information about the coming storm; factors such as wind speeds, size of the storm, and the rate at which the approach occurs were the basics able to be shared. These generalities still did not create a common definition for the potential ramifications of the hurricane in question. The director of the NHC in the 1960s and 70s, Robert H. Simpson, struggled to devise a way to alert residents in a hurricane’s path of the risks they and their locale faced.

Together with Herbert S. Saffir, an engineer who had already spent time working with the United Nations to quantify the consequence of high winds on structures, Simpson and Saffir devised a standardized categorization for hurricanes and their costs to environment and structures. Factors they identified for hurricane forecasts included wind speed, storm surge and probable outcome. The storm surge is a wall of ocean surface that will be pushed ahead and vertical to the eye of the storm, reaching widths of 100 miles and heights over 18 feet, often crashing onto land.

Saffir-Simpson Hurricane Potential Damage Categories

A Category 1 hurricane is the mildest of the five levels of hurricane intensity. With winds of possible speeds ranging from 74 mph to 95 mph, the storm surge potential is 4-5 feet. Potential effects occurring from a category 1 include damage to trees and the flooding of roads along the coastline.

Winds during a Category 2 hurricane range from 96 to 110 mph, causing harm to nearby trees, windows and roofs, even destroying coastal property with storm surges of 6-8 feet high.

The Category 3 hurricane incurs damages and flooding in direct correlation to ever-increasing winds as fast as 111-129 mph. Storm surges for the Category 3 hurricane reach from 9 to 12 feet high.

During the Category 4 hurricane it is possible for winds to reach speeds of 130 to 154 mph. With its concurrent storm surge of 13-18 feet high, inland flooding within 5 miles of the shoreline is likely, and with it the potential ruin of man-made structures.

Once a hurricane has been categorized as Category 5, wind speeds will have accelerated from 155 mph and beyond that to 175 mph. The storm surge from such terrifyingly fast winds will reach heights of 18 feet and beyond. Impossible as it may be to imagine, some 10 miles into the interior off the coast will be flooded and much of the surrounding areas will experience total annihilation.

Although the Saffir-Simpson categories for hurricane speed, storm surge probability, and damage potential provides benefit in understanding the risks of a specific hurricane, no system based on generalities is foolproof. Hurricanes are notorious for their unpredictability: loosing steam or amplifying in intensity in an instant; altering their estimated trajectory; obliterating part of a neighborhood but leaving behind some structures intact.

In May 2010 the Saffir-Simpson scale was streamlined to only categorize wind speed and the possible ensuing damage from a particular category hurricane. To find out more about the new Saffir-Simpson Hurricane Wind Scale with its very specific damage quantifiers, please see the NHC’s website.

Whether a category 1 or a category 5, hurricanes can be lethal and must be respected. Prepare for the impact but more important, get out of its way if you have the counsel to do so.