Categorizing Hurricanes: The Saffir-Simpson Scale

The Saffir-Simpson Hurricane Wind Scale measures the amount of wind damage caused by hurricanes. The speed of the wind determines the category of the storm. Categories range from 1 to 5.

Currently, the Saffir-Simpson Hurricane Wind Scale takes into account only wind speed. Since its development in 1971, it has gone through a few modifications. An earlier version used storm surge and central pressure as well as wind speed to determine damage. This scale was known as the Saffir-Simpson Hurricane Scale. Storm surge in some hurricanes produced larger or smaller surges that placed them in different categories than what their sustained winds would categorize them as. According to NOAA, to avoid public confusion, the scale was modified to only categorize wind speed and its predicted damage.

AccuWeather.com Expert Senior Meteorologist Dan Kottlowski said that the shape of a hurricane and the environment of its projected path plays a significant role in determining the winds of a hurricane.

"Wind is a given; we can measure or estimate pretty accurately. Wind is the most consistent way of measuring the intensity," he said.

Storm surge and central pressure are harder to use to determine hurricane intensity because the information is harder to obtain. To gather central pressure, planes have to fly into the storm or meteorologists rely on satellites, according to Kottlowski.

Models that project storm surge can be relatively accurate but are usually used 48 hours prior to the storm's landfall. Kottlowski said that this does not leave much lead time.

Another modification came in 2012. Some wind speeds that were calculated in miles per hour would fall into a different category than if they had been in knots. To avoid this rounding issue, the National Hurricane Center (NHC) decided to modify the hurricane scale in 5-knot increments to ensure winds calculated in knots and mph would fall into the same category. The Saffir-Simpson Hurricane Wind Scale categorizes hurricane wind gusts in five categories:

Examples of Historic Hurricanes and Their Strengths

Hurricane Katrina made landfall as a Category 3 hurricane on the Saffir-Simpson scale. Maximum sustained winds for Katrina reached 170 mph before making landfall, categorizing Katrina as a Category 5 hurricane. The storm surge for Hurricane Katrina was between 20 to 30 feet, according to NOAA. Hurricane Katrina is ranked the most expensive hurricane to impact the U.S., costing $45.1 billion.

Hurricane Andrew is ranked the second most expensive hurricanes to impact the U.S., costing $22.2 billion. Andrew was categorized as a Category 4 hurricane with maximum sustained winds of 145 mph. Hurricane Andrew made landfall in southern Florida and caused 23 direct deaths and 38 indirect deaths, according to NOAA.

Hurricane Ike made landfall on Sept. 13, 2008, as a Category 2 hurricane. However, its maximum sustained winds reached 145 mph, making it a Category 4 hurricane at one time. A storm surge of about 20 feet was associated with Hurricane Ike. This hurricane is an example of the modification to the Saffir-Simpson scale because the storm surge and wind speeds placed the storm in two different categories.  Ike is ranked the third most expensive hurricanes to impact the U.S.

Hurricane Sandy was a Category 3 hurricane before making landfall. When Sandy made landfall in New Jersey, the intensity was similar to a Category 1; however, the amount of damage was significant. Storm surges were more than 8 feet. Across the central Appalachians, up to 3 feet of snow fell. Sandy claimed 72 lives directly and 75 lives indirectly. It was one of largest storms ever to impact the United States, according to NOAA.

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