What is the difference between a tropical storm and a hurricane?
A slight difference in wind speed is all it takes to seperate the two but for normal discussion the difference is imperceptible.
Hurricane season in the US is here with the nation set to brace itself and batten down the hatches for months as the Atlantic coast is to be savaged. Experts from the National Oceanic and Atmospheric Administration (NOAA) believe 2022 will see above-average hurricane activity, with potentially as many as 10 major hurricanes expected.
Not all storms will reach the damage potential of hurricanes however. These are tropical storms and, although they are the smaller brothers of hurricanes, they cause less significant hurt. This week in September looks to be the most serious of the season so far. Puerto Rico has already been heavily damaged by Tropical Storm Fiona, now on its way to Canada of all places, while Tropical Storm Ian has caused a state of emergency in much of Florida.
A tropical storm is declared at at least 39 mph. They are the intermediate stage on the way to a hurricane, though not every tropical storm will grow into a hurricane. The NOAA thinks there could be as many as 21 tropical storms this year.
In contrast, hurricanes are plenty more fearsome. Winds of a category 1 hurricanes range from 74 to 95 mph to more than 157 mph at category 5. The speed of the wind can cause a storm surge, which is when a wall of sea water is pushed inland, as well as heavy rain.
Why the difference?
Functionally, the two are the same. They are both borne from the same conditions, it is merely the speed of the storm which determines the name. As soon as a tropical storm breaches the 74 mph barrier it is called a hurricane.
What about tornadoes?
Tornadoes are similar to hurricanes though their scale tends to be much smaller. Tornadoes are usually less than 3 miles wide, while hurricanes can be as large as 1000 miles wide. Furthermore, hurricanes tend to form over the sea, while tornadoes form over land.
Tornadoes are produced by strong vertical wind as well as high horizontal termperature changes while hurricanes utilise wek vertical wind alongside low horizontal hanges in atmospheric temperature. The strongest tornadoes can have wind speeds over 300 mph, but hurricanes rarely breach the 200 mph barrier.