How many Category 5 hurricanes made landfall in the United States?

(CNN Spanish) — Of the more than 300 hurricanes that have directly hit the United States since 1851, only four have made landfall as Category 5 hurricanes. Hurricane Ian in September 2022 is not one of them.

The Saffir-Simpson scale divides these events into five categories based on wind speed, storm surge and expected damage. To be included in the highest category, i.e. 5, a hurricane must reach sustained winds of 252 km/h.

It is rare for a hurricane to make landfall in the United States with this intensity: it has happened four times in more than 150 years. National Hurricane Center.

Four category 5 hurricanes hit the US

1. The ‘Labor Day’ hurricane

Until 1953, hurricanes did not receive specific names. That’s why the Category 5 hurricane that hit the Florida Keys in 1935 is commonly known as the ‘Labor Day’ hurricane.

The hurricane formed on August 29 and became a Category 5 hurricane by September 2. As it passed through Florida, Georgia, and the Carolinas, it lost intensity until it lost its status category before moving into the Atlantic.

The storm claimed 408 lives in Florida, which ranked One of the 10 deadliest hurricanes History of America.

2. Cyclone Camille

On August 14, 1969, Camille began to form west of the Cayman Islands. The next day, as it approached Cuba, it was a Category 3 hurricane. Camille became a Category 5 hurricane on August 16 and lasted until the next day, when it made landfall on the Mississippi coast.

The tornado, which killed 256 people in the United States and 3 in Cuba, lost hurricane status as it passed through Tennessee, Kentucky, West Virginia and Virginia. It entered the Atlantic Ocean on 20 August.

3. Hurricane Andrew

Andrew formed off the coast of Africa on August 16, 1992, and rapidly strengthened into a tropical storm. On August 22, Andrew became a hurricane, and a day later it already reached Category 4.

When it hit Florida on August 24, it was believed to be a Category 4 hurricane, but in 2002 it was reclassified as a Category 5 hurricane by landfall.

The hurricane crossed Florida and made landfall again in Louisiana, after which it weakened and lost its hurricane status. Andrew killed 23 people in the United States and three in the Bahamas.

4. Hurricane Michael

Michael in 2018 It made landfall as a Category 5 hurricane near the coast of Mexico and Tyndall Air Force Base in Florida.

It was initially classified as Category 4, but further analysis showed the wind exceeded the threshold to place it in the highest category.

A coastal city in Mexico was devastated by the hurricane. Of the 1,692 buildings in the city, 1,584 were damaged and 809 collapsed. The hurricane directly caused at least 16 deaths in Florida, Virginia, North Carolina and Georgia.

Why do hurricanes tend to weaken when they make landfall?

When a hurricane passes over the ocean, it feeds on warm, moist air from the ocean. The warmer the air below the cyclone, the more moisture the air can hold and therefore the more energy available to strengthen the cyclone.

“The ocean supplies the cyclone with moisture, and the cyclone’s heat engine converts the latent heat in that moisture into strong winds and rain,” explained Binaki Chakraborty, a professor at the Okinawa Institute of Science and Technology in 2020.

But once a hurricane makes landfall and is no longer over the ocean, that critical energy supply that powers the storm is cut off and storms weaken over land.

However, climate change is changing the rules.

According to a study published in 2020Over the past 50 years, the time it takes for a hurricane to weaken after making landfall has increased by 94%.

In the late 1960s, a typical hurricane lost 75% of its intensity on the first day after landfall. In 2020, only 50% of a hurricane was expected to weaken in the first 24 hours after landfall.

This is because human-released greenhouse gases have made our oceans and atmosphere warmer, and the extra warming means hurricanes carry more moisture than in the past, even at higher temperatures, hundreds of kilometers. It also explains why they get so much rain.

With information from CNN’s Drew Kahn.