Hurricane Season: Terms to Know, Tropical Depression, Cyclone, Hurricane Meaning

The Atlantic hurricane season started Friday, meaning for the next five months, people up and down the East Coast and in the Gulf of Mexico will be on guard, waiting for possible storms. But in order to talk about the season and the storms it may bring, there's a certain necessary vocabulary.

Every storm that pops up in the Gulf of Mexico or deeper in the Atlantic Ocean isn't automatically a hurricane. Actually, most of them don't ever become hurricanes. But those storms rarely make the news—only the biggest storms become hurricanes, and even once a storm becomes one, it can still drop down a category if the wind speeds decrease enough.

This year, the Climate Prediction Center and National Oceanic and Atmospheric Administration predicted that there will be five to nine named hurricanes, and one to four of those would be major hurricanes.

hurricane outlook atlantic
The National Oceanic and Atmospheric Administration has released its Atlantic hurricane outlook for the 2018 season. National Oceanic and Atmospheric Administration

Named storms and major hurricanes are different, though they may not seem like it. That's why it's important to understand the vocabulary used to describe these potentially deadly storms. Using the correct terminology doesn't just reduce confusion—it's also important for fully understanding the severity and the risks that come with each type of storm.

Storms that originate in the tropical or subtropical waters of the Atlantic are called tropical cyclones. Depending on the cyclone's strength, it gets a different name. If it has a maximum sustained wind speed of 38 miles per hour or less, the storm is called a tropical depression. Once those winds hit 39 miles per hour, though, the storm is a tropical storm, according to NOAA's National Hurricane Center. Maximum sustained wind speeds above 74 miles per hour officially make the storm a hurricane.

Once a storm is a hurricane, there are various categories that classify the storm based on wind speed and damage it could possibly cause. The Saffir-Simpson Hurricane Wind Scale is used to classify these storms.

Hurricane Categories:

Category 1: When a hurricane is classified as a Category 1, it has 74- to 95-mile-per-hour winds. These storms can do damage to homes like ripping off siding or roofing, and can topple trees and power lines, according to NOAA.

Category 2: The next level of storm has winds between 96 and 110 miles per hour. These storms are extremely dangerous and have the potential to cause significant damage to the roofs and siding of homes.

Category 3: Well-built homes can be damaged in these storms. They come with winds between 111 and 129 miles per hour.

Category 4: This is the level storm NOAA says will cause "catastrophic damage." The wind speeds alone are between 130 and 156 miles per hour and can make the area uninhabitable for months.

Category 5: Winds of 157 miles per hour cause Category 5 storms that destroy homes and cause long-lasting damage to any area they touch.

A flooded street is seen as people deal with the aftermath of Hurricane Maria on September 25, 2017, in San Juan, Puerto Rico. Joe Raedle/Getty Images