Hurricane categories and what they miss
The Saffir-Simpson scale rates hurricanes 1 to 5 by sustained wind alone: Category 1 is 74-95 mph, 2 is 96-110, 3 is 111-129, 4 is 130-156, and 5 is 157 mph or higher. It does not measure storm surge, rainfall flooding, tornadoes, or storm size. Water, not wind, causes about nine in ten U.S. tropical cyclone deaths.
What the five categories actually measure
The Saffir-Simpson Hurricane Wind Scale sorts a hurricane by one number: its peak one-minute sustained wind, measured at the standard height of 10 meters, about 33 feet. Category 1 is 74 to 95 mph, Category 2 is 96 to 110, Category 3 is 111 to 129, Category 4 is 130 to 156, and Category 5 is 157 mph or higher. Category 3 and above are major hurricanes.
That number is a sustained wind, not a gust; gusts run higher, and a gust is usually what takes a roof off. It is also the peak wind anywhere in the storm, usually inside a narrow eyewall ring, so most places never see it. NHC says peak winds likely drop about a category within half a mile of the coastline, and puts wind atop a 30-story building about one category above the surface.
On the live map, a Category 4 label comes from the latest NHC advisory: the strongest wind in the storm, not a forecast for your address.
The scale used to include surge. NHC removed it.
Earlier versions paired each category with a central pressure range and a storm surge range. NHC removed both, plus the flooding-impact statements; the wind-only Saffir-Simpson Hurricane Wind Scale became operational in 2010, to cut public confusion and make the scale more scientifically defensible.
Surge is not about wind speed but about how much water a storm can push: wind field size, how long the wind blows onshore, forward speed, approach angle, the shape of the continental shelf, and the tide it arrives on. Pressure lifts the sea only slightly; wind does nearly all the work.
NHC's own examples: Ike hit Galveston in 2008 as a Category 2, hurricane-force winds reaching 125 miles from the center, peak surge near 20 feet. Charley hit southwest Florida in 2004 as a Category 4, hurricane-force winds reaching at most 25 miles, peak surge about 7 feet. Katrina, a Category 3 at its Louisiana landfall, drove 24 to 28 feet into Mississippi, the highest U.S. surge on record.
Water is what kills, not wind
A National Hurricane Center study of U.S. deaths caused directly by Atlantic tropical cyclones, 1963-2012, found about nine in ten were water deaths: surge roughly half, rainfall flooding about a quarter. Wind caused fewer than one in ten.
Rainfall totals have little to do with category. What matters is how long it rains over one place: forward speed, stalling, terrain lift. Harvey came ashore as a Category 4 in 2017, but the disaster came days later when it stalled over southeast Texas. Nederland recorded 60.58 inches, the highest storm total from any U.S. tropical cyclone on record; nearly all 68 direct deaths were freshwater flooding.
Camille in 1969 was a Category 5 on the Mississippi coast. Two days later its remnants dropped up to 27 inches of rain overnight on Virginia's Blue Ridge and killed 113 people there, hundreds of miles inland, with no hurricane winds. Forward speed and stall timing are among the hardest things to forecast; the Model Lab shows where guidance disagrees.
Why “just a Category 1” is a dangerous phrase
Agnes came ashore in Florida in 1972 as a Category 1 and killed roughly 120 people, most in Pennsylvania and New York, from flooding days later. Irene hit North Carolina as a Category 1 in 2011; its worst damage landed in landlocked Vermont. Floyd, a Category 2 at landfall in 1999, killed mostly through inland freshwater flooding.
Sandy is the cleanest example. Post-tropical when it reached New Jersey in 2012, it carried no category at all, and its tropical-storm-force wind field spanned roughly a thousand miles. That size drove record water levels into New York Harbor. A small intense storm and a large moderate storm are different problems.
The category says nothing about tornadoes. They form mostly in outer rainbands over roughly the eastern half of the storm, usually outside the hurricane-force wind zone, and can spin up well inland a day or more after landfall. Most are weak, short-lived, and hard to warn for.
The phrase fails: it turns a wind measurement into a verdict on total risk. Even on wind alone, Category 1 snaps large branches, topples shallow-rooted trees, and can leave power out for days. The satellite viewer shows the size and structure a single number hides.
The scale is not useless
The category is honest shorthand for one thing: what wind does to buildings. Category 2 to 3 is roughly the step from major roof and siding damage to removal of roof decking and structural damage on well-built frame homes. At 4 and 5, a high share of framed homes lose roof structure or walls, and NHC expects most of the area uninhabitable for weeks or months.
It is also a rate-of-change signal. A storm that jumps from Category 1 to Category 4 in a day has rapidly intensified, and yesterday's forecast no longer describes what you face. That comes from ocean heat and weak shear, which is why the environment maps carry sea surface temperature, ocean heat content, shear, and Saharan dust.
Use your zone, not the number
Evacuation zones are built from surge modeling for your coastline, elevation, and bay geometry. They are not category-based, and not the same as flood insurance zones. Your county or parish emergency management office decides when a zone evacuates; state lookups are on the resources page.
Save the places you care about on the alerts page and EYEWALL builds a Personal Threat Card for each on your device: watches and warnings in effect, how the forecast track relates to that spot, which hazards apply. It summarizes official products; it does not replace them and is not a warning service.
The National Hurricane Center issues watches and warnings. Your local emergency management issues evacuation orders. Those are the authorities. Learn your zone before a storm has a name, find out if your route floods, and treat the category as one input, not the answer.
Eyewall presents live public NOAA / National Hurricane Center data. It is not a warning authority — always follow the NHC and your local emergency management.
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