Explaining hurricane categories: What determines a storm’s rank

How wind speeds are used to determine a hurricane’s severity

FORT LAUDERDALE, FL - SEPTEMBER 10: Trees bend in the tropical storm wind along North Fort Lauderdale Beach Boulevard as Hurricane Irma hits the southern part of the state September 10, 2017 in Fort Lauderdale, Florida. (Photo by Chip Somodevilla/Getty Images) (Chip Somodevilla, 2017 Getty Images)

One of the most defining factors of a hurricane’s severity is the strength and speed of the wind it produces.

Hurricanes are violent storms that produce a number of deadly hazards, especially if they make landfall, including intense winds, a storm surge, rainfall flooding and tornadoes. Weather experts urge people affected by a hurricane to take protective action when any of these hazards present themselves, or when they’re expected to.

Related: Hurricane Ian strikes Cuba, Florida braces for Cat 4 damage

Hurricane winds have the potential to cause significant to “catastrophic” damage to affected communities, depending on how fast those sustained winds are moving. Hurricanes are, in fact, categorized based on the speed of its winds.

The storms, which most often occur in the Atlantic Ocean and the eastern north Pacific Ocean, are placed into one of five categories based on their wind speeds using the Saffir-Simpson Hurricane Wind Scale.

A Category 1 hurricane is the lowest category and causes the least amount of damage, while a Category 5 hurricane is the most dangerous type of hurricane. A Category 1 hurricane is still capable of causing serious damage, though.

Any hurricane identified as a Category 3 or higher is considered a “major” hurricane.

Here’s how each hurricane category is broken down, as explained by the National Hurricane Center:

CategorySustained wind speedType of damage caused by hurricane winds
174-95 mphVery dangerous winds will produce some damage: Well-constructed frame homes could have damage to roof, shingles, vinyl siding and gutters. Large branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days.
296-110 mphExtremely dangerous winds will cause extensive damage: Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected with outages that could last from several days to weeks.
3
(major)
111-129 mphDevastating damage will occur: Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.
4
(major)
130-156 mphCatastrophic damage will occur: Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
5
(major)
157 mph or higherCatastrophic damage will occur: A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. 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 document down below offers more details about the type of damage that can occur from winds during each hurricane category.

It’s also important to note that severe winds are not the only danger posed to residents and communities during a hurricane. A storm surge, for example, is an abnormal rise of water associated with a storm, and it brings the water level above its normal tidal level, infiltrating communities and damaging them. A storm surge can be deadly.

Storm surge is not included on the SSHWS scale ranking hurricanes because there are “too many exceptions,” according to the NHC. For example, Hurricane Katrina, a Category 3 hurricane, produced a 28-foot storm surge, while Hurricane Charley, a Category 4 Hurricane, produced a 6-8-foot storm surge.

Learn more on the NHC’s website right here.


Related resource: Florida evacuation list for Hurricane Ian: Tracking by county, how to find your zone


About the Author:

Cassidy Johncox is a senior digital news editor covering stories across the spectrum, with a special focus on politics and community issues.