Hurricane Lee as a Category 5 hurricane on the early morning of September 8, 2023.

A Category 5 Atlantic hurricane is a tropical cyclone that reaches Category 5 intensity on the Saffir–Simpson hurricane wind scale, within the Atlantic Ocean to the north of the equator. They are among the strongest tropical cyclones that can form on Earth, having 1-minute sustained wind speeds of at least 137 knots (254 km/h; 158 mph; 70 m/s). The United States National Hurricane Center currently estimates that 11 tropical cyclones between 1851 (the first Atlantic hurricane season to be included in the official Atlantic tropical cyclone record) and 1959 peaked as Category 5 hurricanes. However, because technologies such as satellite monitoring were not available until the 1960s, some such cyclones may have remained undetected. Since 1960, 29 Atlantic hurricanes have reached Category 5.

Background

Tracks of all known Category 5 Atlantic hurricanes between 1851 and 2019.

Within the Atlantic Ocean to the north of the Equator, hurricanes are officially monitored by the United States's National Hurricane Center (NHC), however, other meteorological services, such as Météo-France, the United Kingdom's Met Office and Environment Canada also monitor the basin. Within the region, a Category 5 hurricane is a tropical cyclone which reaches Category 5 status on the Saffir–Simpson hurricane wind scale, that is, a tropical cyclone that has 1-minute mean maximum sustained wind speeds of 137 knots (254 km/h; 158 mph; 70 m/s) or greater at 10 metres (32.8 ft) above ground.^[1]

A total of 40 tropical cyclones have been estimated to have peaked as Category 5 hurricanes on the SSHWS, with the first occurrence recorded in 1924. No Category 5 hurricanes were observed officially before 1924. It can be presumed that earlier storms reached Category 5 strength over open waters, but the strongest winds were not measured. Although anemometer, a device used for measuring wind speed, was invented in 1846, during major hurricane strikes the instruments were often blown away or damaged, leaving the hurricane's peak intensity unrecorded. For example, as the Great Beaufort Hurricane of 1879 struck North Carolina, the anemometer cups were blown away when indicating 138 mph (222 km/h).^[2]

As of May 2018, a reanalysis of weather data was ongoing by researchers who may upgrade or downgrade Atlantic hurricanes.^[3] For example, the 1825 Santa Ana hurricane is suspected to have reached Category 5 strength.^[4] Furthermore, paleotempestological research aims to identify past major hurricanes by comparing sedimentary evidence of recent and past hurricane strikes. For example, a "giant hurricane" significantly more powerful than Hurricane Hattie (Category 5) has been identified in Belizean sediment, having struck the region sometime before 1500.^[5]

Records

An October Category 5 that hit Cuba, Florida, and The Bahamas in 1924. It was the first hurricane to be officially recognized as a Category 5 on the modern-day Saffir–Simpson Hurricane Wind Scale.

Officially, the decade with the most Category 5 hurricanes is 2000–2009, with eight Category 5 hurricanes having occurred: Isabel (2003), Ivan (2004), Emily (2005), Katrina (2005), Rita (2005), Wilma (2005), Dean (2007), and Felix (2007). The previous decades with the most Category 5 hurricanes were the 1930s and 1960s, with six occurring between 1930 and 1939.^[6] The most Category 5 hurricanes recorded in a single season is four, in 2005. The most consecutive years to feature at least one Category 5 hurricane each is four, from 2016 to 2019.^[7]

A collage of all Category 5 Atlantic hurricanes since 1980

Nine Atlantic hurricanes—Camille, Allen, Andrew, Isabel, Ivan, Dean, Felix, Irma and Maria—reached Category 5 intensity on more than one occasion; that is, by reaching Category 5 intensity, weakening to a Category 4 status or lower, and then becoming a Category 5 hurricane again. Such hurricanes have their dates shown together. Camille, Andrew, Dean, Felix, Irma, and Maria each attained Category 5 status twice during their lifespans. Allen, Isabel, and Ivan reached Category 5 intensity on three separate occasions. The 1932 Cuba hurricane holds the record for the most time spent as a Category 5 hurricane (although it took place before satellite or aircraft reconnaissance, so this record may be somewhat suspect). Irma holds the record for the longest continuous span as a Category 5 storm in the satellite era.^[6][8]

Of the 40 Category 5 Atlantic hurricanes on record, 1 has been recorded in July, 8 in August, 22 in September, 6 in October, and 1 in November. There have been no officially recorded June or off-season Category 5 hurricanes.^[6]

The July and August Category 5 hurricanes reached their high intensities in both the Gulf of Mexico and the Caribbean. These are the areas most favorable for tropical cyclone development in those months.^[6][9]

September sees the most Category 5 hurricanes, with over half of the total. This coincides with the climatological peak of the Atlantic hurricane season, which occurs in early September.^[10] September Category 5s reached their strengths in any of the Gulf of Mexico, Caribbean, and open Atlantic. These places are where September tropical cyclones are likely to form.^[9] Many of these hurricanes are either Cape Verde hurricanes, which develop their strength due to a long track over warm waters,^[11] or else intensify over the warm Loop Current in the Gulf of Mexico.

All but one of the Category 5 hurricanes in October and November (the exception being Michael) reached their intensities in the western Caribbean, a region that Atlantic hurricanes strongly gravitate toward late in the season.^[9] This is due to the climatology of the area, which sometimes has a high-altitude anticyclone that promotes rapid intensification late in the season, as well as warm waters.

Systems

Number by month

Landfalls

Hurricane Michael as it was making landfall as a Category 5 hurricane in 2018

Nearly all Atlantic Category 5 hurricanes have made landfall at some location while a tropical or subtropical cyclone. This is primarily because of their proximity to land in the Caribbean and Gulf of Mexico, where the usual synoptic weather patterns carry them towards land, as opposed to the westward, oceanic mean track of Eastern Pacific hurricanes.^[68] Nineteen of the storms made landfall at least once while at Category 5 intensity;^[6] 2007 and 2017 are the only years in which two storms made landfall at this intensity.^[6] All but five landfalling systems (the 1944 Great Atlantic hurricane, Carol, Esther, Mitch and Isabel) did so at major hurricane strength.

Many of these systems made landfall shortly after weakening from a Category 5 hurricane. This weakening can be caused by dry air near land, shallower waters due to shelving, interaction with land, eyewall replacement cycles, increased vertical wind shear, or cooler waters near shore.^[48] The only Atlantic Category 5 hurricanes that did not make landfall while a tropical or subtropical cyclone were Hurricane Lee, which still made landfall as an extratropical cyclone in Nova Scotia, and Hurricane Lorenzo, which still brought hurricane-force winds to the Azores. These two storms are therefore not included in the table below.

The following table lists these hurricanes by landfall intensity.

See also

• Atlantic hurricane season
• List of Atlantic hurricanes
• List of Category 4 Atlantic hurricanes
• List of Category 3 Atlantic hurricanes
• List of Category 2 Atlantic hurricanes
• List of Category 5 Pacific hurricanes
• List of Category 4 Pacific hurricanes
• List of Category 3 Pacific hurricanes
• Pacific hurricane season
• List of Pacific hurricanes

References

External links

• NHC web site