Hurricane Irma is an extremely powerful tropical cyclone that is currently making landfall in Cuba and is threatening the Southeastern United States. It is the strongest hurricane ever recorded in the Atlantic basin outside the Caribbean and Gulf of Mexico, and is tied with the 1935 Labor Day hurricane as the strongest landfalling cyclone on record in the Atlantic basin as well as the strongest Atlantic hurricane since Wilma of 2005 in terms of maximum sustained winds, the most intense in terms of pressure since Dean in 2007, and the first of such intensity to make landfall anywhere in the Atlantic since Felix in 2007.
Irma is also the first Category 5 hurricane on record to affect the northern Leeward Islands, and only the second hurricane on record to make landfall in Cuba at such an
intensity, with the other being a hurricane in 1924. A typical Cape Verde hurricane, Irma developed on August 30 near the Cape Verde Islands from a tropical wave that had moved off the west African coast two days prior. It is the ninth named storm, fourth hurricane, and second major hurricane of the 2017 Atlantic hurricane season.
Under favorable conditions, Irma rapidly intensified shortly after formation, becoming a Category 2 hurricane within a mere 24 hours. It became a Category 3 hurricane (and therefore a major hurricane) shortly afterward; however, the intensity fluctuated for the next several days due to a series of eyewall replacement cycles. On September 5, Irma became a Category 5 hurricane, and by early the next day, Irma reached peak intensity with 185 mph (295 km/h) winds and a minimum pressure of 914 mbar (914 hPa; 27.0 inHg). This ties it as the second-strongest Atlantic hurricane by wind speed, surpassed only by Allen of 1980 which reached wind speeds of 190 mph (305 km/h). Irma sustained these 185 mph (295 km/h) winds for 37 hours, surpassing Allen’s record, which had sustained 180 mph (285 km/h) winds for 18 hours. In addition, Irma achieved one of the longest durations of Category 5 strength winds ever on record. Irma’s low pressure also makes it the strongest tropical cyclone worldwide in 2017 so far.
The US National Hurricane Center (NHC) began monitoring a tropical wave over the western coast of Africa on August 26. This wave moved off the coast of the continent late on August 27. Throughout the next two days, showers and thunderstorms associated with the wave became better organized and gradually coalesced into a low pressure area as it passed just south of and through the Cape Verde Islands on August 29, with the NHC stating that any significant organization of the disturbance would result in the classification of a tropical depression.
Further organization over the next 24 hours or so led to classification of the disturbance as Tropical Storm Irma at 15:00 UTC on August 30, based on scatterometer data and satellite estimates. With warm sea surface temperatures and low wind shear, strengthening was anticipated, with the only hindrance being slightly cooler waters and drier air. The nascent storm began developing upper-level poleward outflow as an anticyclone became established over the system, with banding features becoming increasingly evident in satellite images.
Early on August 31, shortly after the development of a central dense overcast (CDO) and an eye feature, Irma rapidly intensified beginning at 09:00 UTC on August 31, with winds increasing from 70 mph (110 km/h) to 115 mph (185 km/h) in only 12 hours. On September 2, a ship passed 60 mi (90 km) to the west of the center of Irma, recording maximum winds of 45 mph (70 km/h), which indicated that the eye of Irma remained compact. A strengthening subtropical ridge over the central North Atlantic pushed Irma from a western to southwestern direction on September 2 and 3. The first aircraft reconnaissance mission departed from Barbados on the afternoon of September 3, discovering an eye 29 mi (47 km) in diameter and surface winds of 115 mph (185 km/h).
On September 4, Hurricane Irma strengthened into a Category 4 hurricane, with winds of 130 mph (215 km/h) at 21:00 UTC. Irma continued deepening and became a Category 5 hurricane by 11:45 UTC on the following day, with winds of 175 mph (280 km/h), making Irma the easternmost Atlantic hurricane of this strength on record, surpassing Hurricane David of 1979. At 15:00 UTC, the National Hurricane Center announced that aircraft reconnaissance indicated that Hurricane Irma had maximum sustained winds of 180 mph (285 km/h). By 00:15 UTC on September 6, Irma’s maximum sustained winds and minimum pressure reached 185 mph (295 km/h) and 916 mbar (916 hPa; 27.0 inHg), respectively.
Only four other Atlantic hurricanes have been recorded with wind speeds of 185 mph (295 km/h) or higher: Wilma, the 1935 Labor Day hurricane, Hurricane Allen of 1980, and Hurricane Gilbert of 1988. In addition, Irma is the strongest hurricane in the Atlantic basin outside of the Caribbean Sea and Gulf of Mexico in recorded history (although reliable records only date to the late 1960s with satellite observations), and its intensity was such as to register on seismographs in Guadeloupe.
At 06:00 UTC on September 6, the center of Irma made landfall along the northern coast of Barbuda at peak strength. This made Irma the equal third-strongest tropical cyclone to make landfall globally – in terms of sustained winds – along with the 1935 Labor Day hurricane and Typhoon Joan of 1959, trailing only typhoons Haiyan of 2013 and Meranti of 2016, which bore winds of 190 mph (310 km/h) at landfall. Irma also tied the 1935 hurricane as the strongest at landfall in the Atlantic basin since records began in 1851. As of the 2:00 a.m. advisory on September 7, Irma had sustained 185 mph (295 km/h) winds for 37 hours, the only tropical cyclone worldwide to have had winds that speed for that long, breaking the previous record of 24 hours set by Typhoon Haiyan.
While maintaining its intensity, Irma made successive landfalls at approximately 12:00 UTC on Sint Maarten and at 17:00 UTC on Ginger Island and Tortola in the British Virgin Islands. Shortly before 06:00 UTC on September 8, Irma made landfall on the Bahamian island Little Inagua. About three hours later, Irma weakened into a Category 4 hurricane but regained Category 5 status 18 hours later.
Irma caused catastrophic damage in Barbuda, Saint Barthélemy, Saint Martin, Anguilla and the Virgin Islands as a Category 5 hurricane. Irma was the strongest hurricane to strike the northern Leeward Islands and one of the worst storms to hit the region, along with Hurricane Donna in 1960 and Hurricane Luis in 1995. As of September 9, the hurricane has caused at least 24 deaths.
As of 5:00 a.m. AST (09:00 UTC) September 9, Hurricane Irma is located within 10 nautical miles of Category 4 on the Saffir–Simpson scale, with gusts to 165 knots (190 mph; 305 km/h). The minimum barometric pressure is 930 millibars (hPa; 27.46 inHg). The system is moving west-northwest at 10 knots (12 mph; 19 km/h). Hurricane-force winds extend up to 60 nautical miles (70 mi; 110 km) from the center of Irma, and tropical-storm-force winds extend outward up to 170 nautical miles (195 mi; 315 km)., about 45 miles (70 km) east of Caibarién, Cuba, and about 245 miles (395 km) south-southeast of Miami, Florida. Maximum sustained winds are 135 knots (155 mph; 250 km/h), a
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