May 17, 2019 - Science

How hurricanes are classified

Damage to a home after Hurricane Michael

Damage done to homes in Florida by Hurricane Michael. Photo: Scott Olson/Getty Images

Hurricanes are classified using the Saffir-Simpson Hurricane Wind Scale — a 1 to 5 rating that's based on maximum sustained wind speed, according to the National Hurricane Center.

Background: The scale also assesses potential property damage from strong winds, with "Category 3" hurricanes and higher considered to be "major" hurricanes. The scale was created by Herbert Saffir and Robert Simpson in 1971 and introduced to the public in 1973. It was updated in 2010 to solely reflect wind speed and not storm surge or other factors.

Here's how the categories are broken down:

  • Category 1
    • Winds: 74–95 mph
    • "Very dangerous winds will produce some damage."
    • Example: Hurricane Nate (October 2017), Hurricane Franklin (August 2017)
  • Category 2
    • Winds: 96–110 mph
    • "Extremely dangerous winds will cause extensive damage."
    • Example: Hurricane Arthur (July 2014), Hurricane Ernesto (August 2012)
  • Category 3 (major)
    • Winds: 111–129 mph
    • Damage: "Devastating damage will occur"
    • Example: Hurricane Katrina (Augst 2005), Hurricane Karl (September 2010)
  • Category 4 (major)
    • Winds: 130–156 mph
    • "Catastrophic damage will occur"
    • Example: Hurricane Harvey (August–September 2017), Hurricane Joaquin (September–October 2015)
  • Category 5 (major)
    • Winds: 157 mph and higher
    • "Catastrophic damage will occur"
    • Example: Hurricane Michael (October 2018), Hurricane Andrew (August 1992)

Yes, but: A "hurricane" is the name given to systems that develop over the Atlantic or the eastern Pacific Ocean. Tropical storms that develop in other places can be called "typhoons" or "cyclones" — and the classification practices for those differ slightly.

Context: Even Category 1 hurricanes can kill dozens, given that the greatest threat is water, not wind. This comes both through a storm surge at the coast and heavy inland rains.

  • There is a growing movement within the meteorology community to rethink the Saffir-Simpson scale to take into account other storm characteristics, including size, surge potential and rainfall.

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