Here are the three Category 5 hurricanes that have hit the US mainland

Story highlights

  • Only three Category 5 hurricanes have ever made landfall in the US
  • Hurricane Irma, with sustained winds of 180 mph, could be one of the strongest

(CNN)If Hurricane Irma strikes South Florida as projected, it would become only the fourth Category 5 storm to ever make landfall in the US mainland.

It's been 25 years since the last Category 5 storm, Hurricane Andrew, made landfall on Florida's southern east coast. Now, as Irma heads northwest, Florida and nearby islands in the Caribbean are bracing for what could be an historic impact.
Here's a look back at the other Category 5 hurricanes that have made landfall in the US:
    • Hurricane Andrew, August 16 - 28, 1992
    • Hurricane Camille, August 14 - 22, 1969
    • The unnamed 'Labor Day' Hurricane, August 29 - September 10, 1935

    TIMELINE

    Hurricane Andrew: According to the National Hurricane Center (NHC), Andrew formed off the coast of Africa on August 16, but quickly strengthened into a tropical storm. On August 22, Andrew became a hurricane, and by the next day it had become a Category 4 hurricane.
    When it hit Florida on August 24, it was originally believed to be a Category 4 storm. But in 2002, it was reclassified as having been a Category 5 hurricane when it made landfall.
    The storm blew over Florida and made landfall again in Louisiana, after which it weakened and lost its status as a hurricane.
    Hurricane Camille: On August 14, 1969, Camille began taking shape west of the Cayman Islands. By the next day, as it approached Cuba, it was Category 3 storm. Camille became a Category 5 hurricane on August 16, a status it held until the next day, when it made landfall on the coast of Mississippi.
    The storm lost hurricane status as it crossed through Tennessee, Kentucky, West Virginia and Virginia. It drifted into the Atlantic Ocean on August 20.
    'Labor Day' Hurricane: Hurricanes weren't given individual names until 1953, so you may have not heard of the unnamed 'Labor Day' hurricane of 1935. It formed on August 29, and by September 2, it had become a Category 5 hurricane and hit the Florida Keys.
    As it passed through Florida, Georgia and the Carolinas, it lost its hurricane status before heading east into the Atlantic.

    WIND STRENGTH

    The National Hurricane Center categorizes hurricanes using the Saffir-Simpson Wind Scale. The scale uses wind speed as the defining factor of which category a hurricane belongs to. Category 5 hurricanes are classified as having winds of 157 mph or higher.
    Hurricanes that are Category 3 and higher are classified as "major hurricanes because of their potential for significant loss of life and damage."
    Hurricane Andrew: Andrew destroyed many of the instruments used to measure wind speed, the NHC says, but one station measured it at 142 mph.
    Hurricane Camille: The NHC says the maximum sustained winds from Camille are unknown for the same reasons as Andrew, but estimates put the wind speed at around 200 mph near the Mississippi coast.
    'Labor Day' Hurricane: No wind measurements are available.

    LIVES LOST

    As of Thursday morning, Hurricane Irma had already claimed six lives throughout the Caribbean. Hopefully, those in Irma's path will be able to evacuate or safely shelter in place.
    But even these Category 5 storms' death tolls don't stand up to the catastrophic loss of life from such storms as Hurricane Katrina, which FEMA estimates killed 1,833 people.
    The NHC considers the deadliest hurricane of all time to be the Galveston Hurricane of 1900, which was responsible for more than 8,000 deaths.
    Hurricane Andrew: 23 deaths in the US and three in the Bahamas
    Hurricane Camille: 256 deaths in the US and three deaths in Cuba
    'Labor Day' Hurricane: 408 deaths in the Florida Keys

    PROPERTY DAMAGE

    According to the NHC, Category 5 storms bring "catastrophic damage."
    • "A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months."
    Irma has quickly become one of the most powerful hurricanes ever recorded in the Atlantic. The hurricane has sustained winds of 180 mph -- well over the 157 mph minimum for Category 5 -- for more than 40 hours, longer than any storm ever before.
    Hurricane Andrew: $26.5 billion in the US, making it the fourth costliest hurricane in the US. Damage in the Bahamas was estimated at $250 million
    Hurricane Camille: $1.42 billion
    'Labor Day' Hurricane: Estimated $6 million