Tropical Weather Systems: Tropical depression, tropical storm and hurricane terms explained

6 Storm Team Weather School

KNOXVILLE, Tenn. (WATE) – We’ve all heard the terms tropical depression, tropical storm and hurricane, but what is the difference between the three?

In our last Weather School edition, we showed you how tropical systems form over those warm waters of the Atlantic, the Gulf, the Caribbean, and that rising air would then sometimes begin to circulate.

Tropical Depression

When that circulation gets strong enough and the winds start picking up to about 30-35 miles per hour and you have a center of circulation, it called a tropical depression.

Tropical Storm

Once those winds jump to about 40 miles per hour, it’s a tropical storm. Winds are stronger and can be up to 73 miles per hour. With stronger winds come damages. As a tropical storm makes its way toward coastlines, and the rising air intensifies, it builds more and more storms near the center of circulation.


Eventually, in a mature system, those winds get above 74 miles per hour. That’s a hurricane with a storm surge and the possibility for tremendous wind damage and heavy rain as it nears a coastline.

And above 74 miles per hour, hurricanes are categorized one through five with category five winds sustained at 150 miles per hour or above. Winds of 150 miles per hour can cause catastrophic damage.

So, again, tropical depression, tropical storm and a hurricane are the three types of tropical weather systems over the Atlantic Gulf and the Caribbean.

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