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Effects of Hurricane Irma in Florida

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Through Cuba and State of emergency

Preparations for the hurricane began nearly a week before it struck the Keys, beginning with Governor Rick Scott declaring a state of emergency on September 4. With both the Atlantic and Gulf coasts of the state threatened, record evacuations ensued with an estimated 6.5 million people relocating statewide. A mandatory evacuation order was issued for all Monroe County—though roughly 25% of residents stayed—and portions of 23 other counties. The large-scale evacuation strained roadways, with gridlock reported along Interstates 75, 95, and Florida's Turnpike. A total of 191,764 people sought refuge in public shelters. All major airports saw disruption of services, resulting in the cancellation of 9,000 flights. Professional and college-level athletics saw substantial schedule adjustments due to the storm.

The storm's large wind field resulted in strong winds across the entire state except for the western Panhandle. The strongest reported sustained wind speed was 112 mph (180 km/h) on Marco Island, while the highest observed wind gust was 142 mph (229 km/h), recorded near Naples, though stronger winds likely occurred in the Middle Florida Keys. Over 7.7 million homes and businesses were without power at some point – about 73% of electrical customers in the state, making Irma the largest power outage relating to a tropical cyclone in United States history. Precipitation was generally heavy to the east of the storm's path, peaking at 21.66 in (550 mm) in Fort Pierce. Heavy rainfall – and storm surge, in some instances – caused at least 32 rivers and creeks to overflow, resulting in significant flooding, especially along the St. Johns River and its tributaries. Many homes and businesses were damaged or destroyed, including over 65,000 structures in West Central and Southwest Florida alone. Agriculture was also hit hard, suffering about $2.5 billion (2017 USD) in damage. It was estimated that the cyclone caused at least $50 billion in damage, making Irma the costliest hurricane in Florida history, surpassing Hurricane Andrew; however, Irma was greatly surpassed in this aspect by Hurricane Ian in 2022. The hurricane left at least 84 fatalities across 27 counties, including 12 at a nursing home due to sweltering conditions and lack of power in the hurricane's aftermath.

Background

A tropical wave moved off the coast of western Africa on August 26. The tropical wave eventually developed into the tenth tropical depression of the season west of the Cape Verde Islands, becoming Tropical Storm Irma. Irma then rapidly intensified into a Category 3 hurricane due to warm sea surface temperatures and low wind shear on September 1. The storm oscillated in intensity over the next few days due to drier air. By September 4, it began rapidly intensifying into a Category 5 hurricane. It made landfall twice in Barbuda and Saint Martin, chronologically, at peak intensity on September 6, with maximum sustained winds of 180 mph and a barometric pressure of 914 mbar. The storm's pressure rose slightly before making another landfall in Virgin Gorda on the same day. Irma began to gradually weaken, forming concentric eyewalls and expanding its wind field. As it moved away from the Virgin Islands, it weakened to a Category 4 hurricane and passed south of the Turks and Caicos Islands.


Irma made landfall on Little Inagua in the Bahamas as a high-end Category 4 hurricane on September 8. The hurricane then re-intensified, reaching Category 5 intensity east of Cuba before making landfall in Cayo Romano, Cuba, on September 9. As it moved along the northern coast of Cuba, the eye became cloud-filled and the intensity fell to a high-end Category 2 hurricane. Irma's forward speed slowed and began to move northwestward toward Florida due to a complex steering pattern, which moved around the southwestern edge of the subtropical high and a low-pressure system over the continental United States. Over the Florida Straits, Irma restrengthened and re-attained Category 4 intensity. The hurricane's wind field increased in size, with hurricane-force winds spanning 80 mi and gale-force winds spanning 220 mi before making landfall in Cudjoe Key, Florida, at 13:00 UTC on September 10, as a low-end Category 4 hurricane. The storm weakened to a low-end Category 3 hurricane before making its final landfall in Marco Island, Florida, at 19:30 UTC. Irma accelerated to the north-northwest, weakening due to wind shear, land interaction, and dry air. It passed east of Tampa as a weak Category 1 hurricane before eventually weakening to a tropical storm and exiting the state into Georgia on September 11. It degenerated to a remnant low in Alabama on September 12.

Irma was the first major hurricane to strike the state since Wilma in 2005 and the first Category 4 hurricane to make landfall in Florida since Charley in 2004. Irma was only the second hurricane to hit Florida since Wilma, the other being Hermine in 2016. Due to few very intense hurricanes since Hurricane Andrew in 1992, there was concern that many Floridians never experienced or did not recall experiencing a hurricane as strong as Irma was projected to be at landfall, with significant growth in population and assets during the previous 25 years.

Irma struck the state less than two weeks after Potential Tropical Cyclone Ten had caused the worst flooding seen in western Florida in at least 20 years, which worsened the disaster in the region.

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