Weather

Hurricane Categories Don't Tell You Anything About The Water

The Hurricane wind scale classifies storms into five wind speed categories — but storms lower on that scale can still cause life-threatening flooding.

Hurricane Categories Don't Tell You Anything About The Water
National Oceanic and Atmospheric Administration
SMS

Most hurricanes that strike the U.S. are not major storms: only about a third of them are category 3 or higher. But a hurricane's category doesn't convey all of its risks. 

Categories only measure wind speed. They don't account for the area a storm covers or measure rainfall or storm surge — which are deadlier than hurricane winds, on average. 

And recent history shows that a low-category storm can do as much or more water damage than a storm with stronger winds. 

Hurricane Katrina made landfall as a Category 3 storm. Sandy had Category 1 winds when it flooded New York City. Much of the flooding from Harvey came while it was a tropical storm — below Category 1 on the wind scale. 

What Happens When A Hurricane Stalls
What Happens When A Hurricane Stalls

What Happens When A Hurricane Stalls

Forecasters say Hurricane Florence could stall right as it makes landfall, like Hurricane Harvey did in 2017. This could lead to even more rain.

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Forecasters can't say for sure yet whether future hurricanes will move slowly like Florence or Harvey did.  But they are confident that the storms will drop more rain overall — which may increase flooding risks on the ground.