2017 Atlantic hurricane season

Season overview

The site's archive tracks 19 systems in 2017. Seventeen reached tropical storm strength, ten became hurricanes, six reached major hurricane strength and two, Irma and Maria, reached Category 5. The other two tracks are Tropical Depression Four, which never reached tropical storm strength, and Potential Tropical Cyclone Ten, a disturbance off the southeastern United States that never became a tropical cyclone. The National Hurricane Center's best track gives the same totals of 17 named storms, 10 hurricanes and 6 major hurricanes, and counts 18 tropical depressions because it leaves out the potential tropical cyclone.

Accumulated cyclone energy reached 224.9 units, among the highest totals in the Atlantic record. Three storms, Irma, Jose and Maria, each generated more than 40 units on their own, something no earlier season had produced. The busiest stretch came in September, which produced more cyclone energy than any other month on record in the basin.

Early outlooks expected a near-average or quieter year because an El Niño seemed likely to develop and suppress Atlantic activity. It never did. The equatorial Pacific cooled through the summer instead, reaching La Niña levels by November, while tropical Atlantic waters that had been cooler than normal warmed quickly by late May. Weaker trade winds, lower pressures and more mid-level moisture followed, and forecasters raised their numbers through the summer.

How the season unfolded

Tropical Storm Arlene formed from a non-tropical low in the central Atlantic in April, only the second tropical storm on record to form in that month, and meandered over open water for about two days. June brought Tropical Storm Bret, which formed southeast of Trinidad and crossed the southern Windward Islands, and Tropical Storm Cindy, a large, sprawling storm that came ashore just east of the Louisiana and Texas border with heavy rain along the northern Gulf Coast.

July added Tropical Depression Four, Tropical Storm Don and Tropical Storm Emily, which developed unexpectedly in the eastern Gulf of Mexico and made landfall just south of Tampa Bay. Although the storm count ran ahead of normal, these early systems were weak and short-lived, and the season's first five named storms produced the lowest combined cyclone energy on record for that stage of a season.

The pattern changed in August. Hurricane Franklin became the season's first hurricane on August 9 before striking eastern mainland Mexico, and Hurricane Gert followed over open water between Bermuda and the United States. Every named storm from Franklin through Ophelia in October became a hurricane, a run of ten in a row that is the longest of the satellite era.

From late August to late September the basin rarely rested. Harvey, Irma, Jose, Katia, Lee and Maria overlapped across the Gulf of Mexico, the Caribbean and the open Atlantic. Hurricane Jose, a long-lived Cape Verde storm, became the season's longest-tracked system on the map, reaching Category 4 east of the Leeward Islands, looping over the southwestern Atlantic and lingering off New England as a tropical storm. Hurricane Lee dissipated, regenerated over the subtropical Atlantic and grew into a Category 3 hurricane far from land.

October brought Hurricane Nate, Hurricane Ophelia and the brief Tropical Storm Philippe, which with a non-tropical system spread gusty winds and heavy rain across Cuba, South Florida and the Bahamas. Tropical Storm Rina closed the season, moving north over the central Atlantic without affecting land and becoming extratropical on November 9.

Strongest storms

Irma was the season's strongest storm. It formed near the Cabo Verde Islands on August 30, became a major hurricane quickly and reached its peak of 155 kt on September 5, with a minimum pressure of 914 hPa early the next day. At the time that was the strongest sustained wind on record for an Atlantic hurricane outside the Gulf of Mexico and the Caribbean. Irma held Category 5 intensity as it crossed Barbuda, St. Martin and the British Virgin Islands on September 6, and regained it before striking Cuba.

Maria produced the season's lowest pressure. It strengthened from a tropical storm into a Category 5 hurricane in about two days, reaching 145 kt as it came ashore on Dominica early on September 19. After a brief setback over the island it peaked at 150 kt, with a pressure of 908 hPa about 25 n mi south of St. Croix early on September 20. That pressure is the lowest on record for any Atlantic hurricane east of 70°W, breaking the mark Irma had set two weeks earlier.

Four other storms reached major hurricane strength. Jose peaked at 135 kt on September 8, just days after Irma passed through the same waters. Harvey reached 115 kt at landfall in Texas. Lee and Ophelia each peaked at 100 kt over the open Atlantic, and Ophelia, spending its whole life in the far eastern Atlantic southwest of the Azores, became the farthest-east major hurricane of the satellite era.

Notable landfalls and impacts

Harvey began as a weak tropical storm that crossed Barbados and St. Vincent and dissipated over the central Caribbean. Its remnants regenerated in the Bay of Campeche on August 23, and it strengthened rapidly into a Category 4 hurricane that came ashore near Rockport, Texas, early on August 26 with winds of 115 kt. The storm then stalled near the coast for four days, and rain totals peaked at 60.58 inches near Nederland, the highest from any tropical cyclone in United States records, with catastrophic flooding across the Houston area. The National Hurricane Center counts at least 68 direct deaths, all in Texas, and about 35 indirect deaths, and NOAA estimates damage at $125 billion in 2017 dollars.

Irma made seven landfalls, four of them at Category 5. On Barbuda about 95 percent of structures were damaged or destroyed, and the island was left uninhabited for the first time in some 300 years. Irma then struck Cuba near Cayo Romano at Category 5, the country's first landfall at that strength since 1924, before crossing the Florida Keys near Cudjoe Key at Category 4 and striking Marco Island at Category 3 on September 10. The National Hurricane Center counts 46 direct deaths across the Caribbean and the southeastern United States, 10 of them in the United States, where a further 82 deaths were indirect. NOAA puts damage in the United States at about $50 billion, in 2017 dollars.

Maria left Dominica largely in ruins, with 31 direct deaths and 34 people missing, and at least $1.31 billion in damage according to media reports cited by the National Hurricane Center. It crossed Puerto Rico near Yabucoa on September 20 with winds near 135 kt, knocking down most of the island's utility poles and all its transmission lines and cutting power to essentially all 3.4 million residents. The government of Puerto Rico, drawing on a George Washington University study, estimates 2,975 deaths on the island, combining direct and indirect deaths. NOAA estimates damage in Puerto Rico and the U.S. Virgin Islands at $90 billion, in 2017 dollars.

Nate crossed northeastern Nicaragua and eastern Honduras as a tropical storm, and its rains triggered floods and mudslides that media reports tie to 45 deaths across Central America, including 16 in Nicaragua and 13 in Costa Rica. Costa Rican authorities reported $562 million in damage. Racing across the Gulf of Mexico, Nate came ashore at the mouth of the Mississippi River and then near Biloxi, Mississippi, on October 8 as a Category 1 hurricane, causing about $225 million in United States damage and two indirect deaths.

Other storms reached land at lower strength. Katia came ashore near Tecolutla, Mexico, as a Category 1 hurricane on September 9, and a mudslide from its rain killed two people in Xalapa. After becoming extratropical, Ophelia hit southwestern Ireland on October 16 as a powerful storm, the worst to affect the country in 50 years; three people died there, and more than 360,000 customers in Ireland lost power.

Records, names and warning practice

Harvey was the first major hurricane to strike the United States since Wilma in 2005, and Harvey and Irma were the first pair of Category 4 hurricanes to strike the country in the same season. With Irma at Barbuda and Maria at Dominica, 2017 became only the second season, after 2007, with two hurricanes making landfall at Category 5 intensity.

The season also marked a change in how warnings were issued. Starting in 2017 the National Hurricane Center could issue advisories, along with tropical storm watches and warnings, for disturbances that were not yet tropical cyclones but were likely to become one and bring storm conditions to land within 48 hours. Bret was the first system handled this way, and Potential Tropical Cyclone Ten off the Carolinas in late August was the first that never became a tropical cyclone at all.

In April 2018 the World Meteorological Organization retired the names Harvey, Irma, Maria and Nate because of the deaths and damage they caused, the most names retired from a single season since 2005. Harold, Idalia, Margot and Nigel replaced them when the list was next used in 2023.