Hurricane Irma
Hurricane Irma was an extremely powerful and devastating tropical cyclone that caused extensive damage and multiple deaths across the Antilles and Eastern United States in September 2017. Irma was the first Category 5 hurricane to strike the Leeward Islands on record, though it was followed by Hurricane Maria, which struck the region at Category 5 intensity as well two weeks later. At the time, Irma was considered the most powerful hurricane on record in the open Atlantic region, outside of the Caribbean Sea and Gulf of Mexico, until it was surpassed by Hurricane Dorian two years later. It was also the third-strongest Atlantic hurricane at landfall ever recorded, just behind the 1935 Labor Day hurricane, Hurricane Melissa, and Dorian.
The ninth named storm, fourth hurricane, second major hurricane, and first Category 5 hurricane of the extremely active 2017 Atlantic hurricane season, Irma developed from a tropical wave near the Cape Verde Islands on August 30. Favorable conditions allowed Irma to rapidly intensify into a Category 3 hurricane on the Saffir–Simpson wind scale by late on August 31. The storm's intensity fluctuated between Categories 2 and 3 for the next several days, due to a series of eyewall replacement cycles. On September 4, Irma resumed intensifying, becoming a Category 5 hurricane by early on the next day. Early on September 6, Irma peaked with 1-minute sustained winds of and a minimum pressure of. Irma was the second-most intense tropical cyclone worldwide in 2017 in terms of barometric pressure, and the strongest worldwide in 2017 in terms of wind speed. Another eyewall replacement cycle caused Irma to weaken back to a Category 4 hurricane, but the storm re-attained Category 5 status before making landfall in Cuba. Although Irma briefly weakened to a Category 2 storm while making landfall on Cuba, the system re-intensified to Category 4 status as it crossed the warm waters of the Straits of Florida, before making landfall on Cudjoe Key on September 10. Irma then weakened to Category 3 status, prior to another landfall in Florida on Marco Island later that day. The system degraded into a remnant low over Alabama and ultimately dissipated on September 13 over Missouri.
Irma caused widespread and catastrophic damage throughout its long lifetime, particularly in the northeastern Caribbean and the Florida Keys. It was also the most intense hurricane to strike the continental United States since Katrina in 2005, the first major hurricane to make landfall in Florida since Wilma in the same year, and the first Category 4 hurricane to strike the state since Charley in 2004. The storm caused catastrophic damage in Barbuda, Saint Barthélemy, Saint Martin, Anguilla, and the Virgin Islands as a Category 5 hurricane. The hurricane caused at least 134 deaths: one in Anguilla; one in Barbados; three in Barbuda; four in the British Virgin Islands; 10 in Cuba; 11 in the French West Indies; one in Haiti; three in Puerto Rico; four on the Dutch side of Sint Maarten; 92 in the contiguous United States, and four in the U.S. Virgin Islands. The word Irmageddon was coined soon after the hurricane to describe the damage caused by the hurricane. Hurricane Irma was the top Google searched term in the U.S. and globally in 2017.
Meteorological history
A tropical wave left the west coast of Africa on August 27, producing a large area of deep convection. Over the following days, convection became more concentrated over the northern part of the disturbance, and a surface circulation developed by August 30. The National Hurricane Center estimates that the disturbance developed into a tropical depression around 00:00 UTC August 30, about 120 nautical miles southwest of the Cape Verde Islands. Six hours later, the depression intensified into Tropical Storm Irma, the ninth named storm of the 2017 Atlantic hurricane season. Located over warm sea surface temperatures, and within an environment of low wind shear, Irma underwent rapid intensification. The formation of an eye around 06:00 UTC on August 31 signified Irma's strengthening into a hurricane, just 30 hours after formation. Turning to the northwest as the ridge steering the cyclone weakened, Irma rapidly intensified into a major hurricane by 00:00 UTC September 1. Within a 48-hour period, the hurricane's intensity had increased by. Fluctuations in intensity occurred over the next few days due to internal processes, as the first aircraft reconnaissance mission into Irma discovered an eye in diameter and surface winds of on September 3.As Irma continued approaching the Leeward Islands, the hurricane underwent a second and more robust period of rapid intensification on September 4, becoming a Category 5 hurricane early the following day. The extremely powerful hurricane continued to strengthen, with maximum sustained winds peaking at shortly afterwards. Irma acquired annular characteristics around this time, with the storm exhibiting a large, symmetric central dense overcast. At 05:45 UTC on September 6, Irma made landfall along the northern coast of Barbuda at peak intensity, with the storm's central minimum pressure having bottomed out at – this was the lowest minimum pressure in the Atlantic since Dean in 2007; the storm also made landfall with maximum sustained winds of. Irma continued to maintain its peak intensity until 12:00 UTC on September 6 and made additional successive landfalls on that same day, at 11:15 UTC on Sint Maarten, and at 16:30 UTC on Virgin Gorda, in the British Virgin Islands.
Irma maintained Category 5 strength for several days as it passed north of the Greater Antilles. After beginning an eyewall replacement cycle, Irma weakened to a Category 4 hurricane as it passed south of the Turks and Caicos Islands early on September 8, subsequently ending the 60-hour continuous period of Irma maintaining Category 5 intensity, the second-longest any Atlantic storm had maintained winds above – behind only the 1932 Cuba hurricane. The hurricane then began tracking more to the west due to the intensification of a subtropical ridge to its north. Once the eyewall replacement cycle was complete, Irma began to re-intensify, and it attained Category 5 intensity for the second time at 18:00 UTC that day east of Cuba. The very powerful hurricane then made landfall in Cayo Romano, Cuba, at 03:00 UTC on September 9, with winds of. This made Irma only the second Category 5 hurricane to strike Cuba in recorded history, after the 1924 Cuba hurricane. As the eye of Irma moved along the northern coast of Cuba, quick weakening ensued due to extended land interaction, with the eye becoming cloud-filled. Irma bottomed out as a high-end Category 2 storm later on September 9.
File:Katia, Irma, Jose 2017-09-08 1745Z–1935Z.jpg|thumb|left|upright=1.25|Three simultaneously active hurricanes on September 8. From left to right: Katia, Irma, and Jose, the first occurrence since 2010.
After slowing down late that day, the hurricane turned northwestward towards Florida. This motion resulted from Irma rounding the southwestern edge of the subtropical high to its northeast and a low-pressure system that was located over the continental United States, to its northwest. Moving over the warm waters of the Straits of Florida, Irma quickly re-intensified to a Category 4 hurricane at 06:00 UTC on September 10, as deep convection improved and the eye became better defined. The cyclone made landfall in Cudjoe Key, Florida, at 13:00 UTC on September 10, at Category 4 intensity, with winds of. Increasing wind shear and land interaction caused the satellite appearance of the storm to become ragged later that day, and Irma weakened to Category 3 intensity before making its seventh and final landfall at 19:30 UTC, in Marco Island, Florida, with sustained winds of. Once Irma had moved inland, it began to accelerate to the north-northwest, while rapid weakening began to occur due to the increasing wind shear, land interaction, and dry air, with the storm falling below Category 3 intensity hours after landfall. Irma finally weakened to a tropical storm on September 11 as it entered southern Georgia. The greatly weakened storm turned more northwestward and degenerated to a remnant low as it crossed into Alabama by 06:00 UTC September 12. The remnant low continued to diminish in strength as it progressed northwestward, dissipating over Missouri the following day.
Preparations
Caribbean
Given that Irma's forecast track was along much of the Caribbean island chain, hurricane warnings were issued for the northern Leeward Islands, Puerto Rico, and parts of Hispaniola on September 5.In Antigua and Barbuda, residents safeguarded their homes and cleaned up their properties in anticipation of strong winds. Emergency crews were put on standby at public shelters and hospitals by September 5 to assist with any evacuations. Expecting a direct hit, more than half of the residents on Barbuda took shelter, and relief supplies were preemptively mobilized. The National Emergency Management Organization on Saint Lucia urged small craft operators and swimmers to be mindful of forecasts for high surf. Small Craft Warnings and High Surf Advisories were hoisted for Dominica, where residents were urged to remain vigilant of the potential for high waves, landslides, and flooding.
In Guadeloupe, low-lying and cliff-edge homes were evacuated at the threat of flooding and erosion. Schools and public businesses closed on September 5 and 6. Hospitals stocked up on three days' worth of supplies and checked the functionality of their generators. Of the island's 32 communes, 22 activated their emergency plans; 1,500 people were urged to take shelter. The island sustained relatively minor damage and became the base for relief efforts on Saint Martin and Saint Barthélemy. Though the core of the hurricane was expected to remain north of the island, a yellow alert was issued for Martinique due to the likelihood of rough seas. The island dispatched relief supplies and military reinforcements to its neighboring islands of Guadeloupe, Saint Martin. and Saint Barthélemy, which faced a greater risk of a direct impact.
On September 4, Puerto Rico declared a state of emergency. By September 6, the U.S. Federal Emergency Management Agency had deployed response teams in Puerto Rico and the United States Virgin Islands. Supplies, including food rations, medical supplies, and blankets, were pre-staged in strategic locations on the islands for distribution.
On September 5, the Dominican Republic activated the International Charter on Space and Major Disasters, thus providing for humanitarian satellite coverage; the United States and Haiti followed suit two days later. According to officials, 11,200 people were evacuated from vulnerable areas prior to the storm's arrival. Approximately 7,400 tourists were moved to Santo Domingo, away from beach resorts. In Haiti, government officials and aid organizations struggled with early preparation and evacuation efforts. While some officials blamed reluctance and indifference on the part of the population, others "admitted they were not prepared for the onslaught and no mandatory evacuation orders were in place ahead of Irma's approach." Local officials contended that they had not received promised funds, supplies, or equipment from the national government. The United Nations Stabilization Mission in Haiti prepared its 1,000 peacekeepers and engineers to assist.
In the Turks and Caicos, evacuation orders were issued for low-lying areas starting September 5. Schools were closed, government buildings were boarded up, and shelters were opened. Officials spread warnings to residents in English, Creole, and Spanish via social media, radio, SMS text, and WhatsApp. In The Bahamas, the government began preparations the week prior to the hurricane's arrival, including securing national sports facilities to use as shelters. By September 7, the government had evacuated 1,609 people by air from the southern islands, including 365 from Bimini. Controlled cutting of the power supply to southern and central Bahamian islands was conducted in advance of the storm. Shelters were made available, though usage was low due to most evacuees staying with family on other islands. Of the 2,679 foreign tourists still in The Bahamas on September 7, about 1,200 were being housed at Atlantis Paradise Island, one of the most hurricane-ready structures in the country.
In Cuba, meteorologists did not initially predict a direct hit. Fuel conservation was enacted in Camagüey Province to ensure that enough would be available during post-storm power outages. The Civil Defense evacuated nearly one million people from low-lying areas, including thousands of Canadian and European tourists in the Jardines del Rey. Dolphins at a Cayo Guillermo resort were evacuated by helicopter.