As Hurricane Milton churns towards Florida threatening destructive damage, the storm's constantly changing wind speeds have likely left many wondering what exactly determines the category of a hurricane.
Previously a Category 5 storm, Milton has weakened to a Category 3 as it nears landfall near the Tampa Bay area, which could land a once-in-a-century direct hit on Tampa and St. Petersburg.
With shifting wind speeds making the category of a particular storm fluctuate, many are wondering what makes a storm classified under a certain category.
Here's a look at the hurricane categories and how they work:
How high do hurricane categories go?
Hurricane categories are based on what is known as the Saffir-Simpson Hurricane Wind Scale.
The rating categorizes hurricanes on a scale of 1 to 5 based on sustained wind speeds, according to the National Weather Service.
Weather
"This scale estimates potential property damage," the NWS reports. "Hurricanes reaching Category 3 and higher are considered major hurricanes because of their potential for significant loss of life and damage. Category 1 and 2 storms are still dangerous, however, and require preventative measures."
The wind speeds are calculated using a one-minute average.
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Here's how they break down:
| Category One Hurricane Winds 74-95 mph. Very dangerous winds will produce some damage |
| Category Two Hurricane Winds 96-110 mph. Extremely dangerous winds will cause extensive damage |
| Category Three Hurricane Winds 111-129 mph. Devastating damage will occur |
| Category Four Hurricane Winds 130-156 mph. Catastrophic damage will occur |
| Category Five Hurricane Winds 157 mph or higher. Catastrophic damage will occur |
In a Category Five storm, "a high percentage of framed homes will be destroyed, with total roof failure and wall collapse," according to the scale.
"Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months," the description states.
Is there a Category 6?
Earlier this year, some experts proposed adding a Category 6 to the ranking for storms with winds that exceed 192 miles per hour, though no such category has been officially created so far.
Several experts told The Associated Press they don't think that category is necessary. They said it could even give the wrong signal to the public because it's based on wind speed, while water is by far the deadliest killer in hurricanes.
What causes a hurricane?
A hurricane is a tropical cyclone with maximum sustained winds of 74 mph or higher that typically registers as a Category 1 or 2 on the Saffir-Simpson Hurricane Wind Scale.
"Hurricanes are powerhouse weather events that suck heat from tropical waters to fuel their fury. These violent storms form over the ocean, often beginning as a tropical wave—a low pressure area that moves through the moisture-rich tropics, possibly enhancing shower and thunderstorm activity," the National Weather Service reports. "As this weather system moves westward across the tropics, warm ocean air rises into the storm, forming an area of low pressure underneath. This causes more air to rush in. The air then rises and cools, forming clouds and thunderstorms. Up in the clouds, water condenses and forms droplets, releasing even more heat to power the storm."
A Category 1 storm has sustained wind speeds between 74 mph and 95 mph, and a Category 2 storm is between 96 mph and 110 mph.
A major hurricane is a tropical cyclone with maximum sustained winds of 111 mph or higher that is classified as Category 3, 4 or 5.
