The 2017 Atlantic hurricane season was a hyperactive, deadly, and extremely destructive season, featuring 17 named storms, ranking alongside 1936 as the fifth-most active season since records began in 1851. The season also featured both the highest total accumulated cyclone energy (ACE) and the highest number of major hurricanes since 2005. All ten of the season's hurricanes occurred in a row, the greatest number of consecutive hurricanes in the satellite era, and tied for the greatest number of consecutive hurricanes ever observed in the Atlantic basin since records began in 1851. In addition, it was by far the costliest season on record, with a preliminary total of approximately $281.14 billion (USD) in damages, which is about $100 billion higher than the total of the 2005 season. In addition, essentially all of the season's damage was due to three of the season's major hurricanes — Harvey, Irma, and Maria. This season is also one of only six years on record to feature multiple Category 5 hurricanes, and only the second after 2007 to feature two hurricanes making landfall at that intensity. This season is the only season on record in which three hurricanes each had an ACE of over 40: Irma, Jose, and Maria.
The season officially began on June 1 and ended on November 30. These dates historically describe the period of year when most tropical cyclones form in the Atlantic basin. However, as shown by Tropical Storm Arlene in April, the formation of tropical cyclones is possible at other times of the year. In mid-June, Tropical Storm Bret struck the island of Trinidad, which is only rarely struck by tropical cyclones due to its low latitude. In late August, Hurricane Harvey became the first major hurricane to make landfall in the United States since Wilma in 2005, while also setting the record for the costliest tropical cyclone on record, as well as the most rainfall dropped by a tropical cyclone in the United States. In early September, Hurricane Irma became the first Category 5 hurricane to impact the northern Leeward Islands on record, later making landfall in the Florida Keys as a large Category 4 hurricane. In terms of maximum sustained winds, Irma is tied with the 1935 Labor Day hurricane as the strongest hurricane ever to make landfall in the Atlantic basin and is the strongest hurricane ever recorded in the Atlantic Ocean outside of the Gulf of Mexico and Caribbean Sea. In late September, Hurricane Maria became the first Category 5 hurricane to strike the island of Dominica on record. It later made landfall in Puerto Rico as a high-end Category 4 hurricane. In early October, Hurricane Nate became the fastest-moving tropical cyclone in the Gulf of Mexico while also becoming the fourth hurricane of the year to hit the overall United States. Slightly over a week later, Hurricane Ophelia became the easternmost major hurricane in the Atlantic basin on record, and later impacted most of Northern Europe as an extratropical cyclone.
Initial predictions for the season anticipated that an El Niño would develop, lowering storm activity. However, the predicted El Niño failed to develop, with cool-neutral conditions developing instead, later progressing to a La Niña – the second one in a row. This led forecasters to upgrade their predicted totals, with some later anticipating that the season could be the most active since 2012.
Beginning in 2017, the National Hurricane Center (NHC) had the option to issue advisories, and thus allow watches and warnings to be issued, on disturbances that are not yet tropical cyclones but have a high chance to become one, and are expected to bring tropical storm or hurricane conditions to landmasses within 48 hours. Such systems are termed "Potential Tropical Cyclones". The first storm to receive this designation was Potential Tropical Cyclone Two, which later developed into Tropical Storm Bret, east-southeast of the Windward Islands on June 18. In addition, the numbering that a potential tropical cyclone receives would be retained for the rest of the hurricane season, meaning that the next tropical system would be designated with the following number, even though potential tropical cyclones do not qualify as tropical cyclones. This was first demonstrated with Potential Tropical Cyclone Ten, which failed to develop into a tropical cyclone.
|2017 Atlantic hurricane season|
Season summary map
|First system formed||April 19, 2017|
|Last system dissipated||November 9, 2017|
|• Maximum winds||175 mph (280 km/h)
|• Lowest pressure||908 mbar (hPa; 26.81 inHg)|
|Total fatalities||≥ 477–1,492 total (with uncertainty)|
|Total damage||≥ $281.14 billion (2017 USD)
(Costliest tropical cyclone season on record)
|Record high activity||28||15||7†|
|Record low activity||4||2†||0†|
|TSR||December 13, 2016||14||6||3|
|TSR||April 5, 2017||11||4||2|
|CSU||April 6, 2017||11||4||2|
|TWC||April 17, 2017||12||6||2|
|NCSU||April 18, 2017||11–15||4–6||1–3|
|TWC||May 20, 2017||14||7||3|
|NOAA||May 25, 2017||11–17||5–9||2–4|
|TSR||May 26, 2017||14||6||3|
|CSU||June 1, 2017||14||6||2|
|UKMO||June 1, 2017||13*||8*||N/A|
|TSR||July 4, 2017||17||7||3|
|CSU||July 5, 2017||15||8||3|
|CSU||August 4, 2017||16||8||3|
|TSR||August 4, 2017||17||7||3|
|NOAA||August 9, 2017||14–19||5–9||2–5|
|* June–November only.
† Most recent of several such occurrences. (See all)
Ahead of and during the season, several national meteorological services and scientific agencies forecast how many named storms, hurricanes and major (Category 3 or higher on the Saffir–Simpson scale) hurricanes will form during a season and/or how many tropical cyclones will affect a particular country. These agencies include the Tropical Storm Risk (TSR) Consortium of the University College London, the National Oceanic and Atmospheric Administration (NOAA) and Colorado State University (CSU). The forecasts include weekly and monthly changes in significant factors that help determine the number of tropical storms, hurricanes, and major hurricanes within a particular year. Some of these forecasts also take into consideration what happened in previous seasons and the dissipation of the 2014–16 El Niño event. On average, an Atlantic hurricane season between 1981 and 2010 contained twelve tropical storms, six hurricanes, and two major hurricanes, with an Accumulated Cyclone Energy (ACE) index of between 66 and 103 units.
The first forecast for the year was issued by TSR on December 13, 2016. They anticipated that the 2017 season would be a near-average season, with a prediction of 14 named storms, 6 hurricanes, and 3 major hurricanes. They also predicted an ACE index of around 101 units. On December 14, CSU released a qualitative discussion detailing five possible scenarios for the 2017 season, taking into account the state of the Atlantic Multidecadal Oscillation and the possibility of El Niño developing during the season. TSR lowered their forecast numbers on April 5, 2017 to 11 named storms, 4 hurricanes, and 2 major hurricanes, based on recent trends favoring the development of El Niño. The next day, CSU released their prediction, also predicting a total of 11 named storms, 4 hurricanes, and 2 major hurricanes. On April 17, The Weather Company released their forecasts, calling for 2017 to be a near-average season, with a total of 12 named storms, 6 hurricanes, and 2 major hurricanes. The next day, on April 18, North Carolina State University released their prediction, also predicting a near-average season, with a total of 11–15 named storms, 4–6 hurricanes, and 1–3 major hurricanes. On May 20, The Weather Company issued an updated forecast, raising their numbers to 14 named storms, 7 hurricanes, and 3 major hurricanes to account for Tropical Storm Arlene as well as the decreasing chance of El Niño forming during the season. On May 25, NOAA released their prediction, citing a 70% chance of an above average season due to "a weak or nonexistent El Niño", calling for 11–17 named storms, 5–9 hurricanes, and 2–4 major hurricanes. On May 26, TSR updated its prediction to around the same numbers as its December 2016 prediction, with only a minor change in the expected ACE index amount to 98 units.
CSU updated their forecast on June 1 to include 14 named storms, 6 hurricanes, and 2 major hurricanes, to include Tropical Storm Arlene. It was based on the current status of the North Atlantic Oscillation, which was showing signs of leaning towards a negative phase, favoring a warmer tropical Atlantic; and the chances of El Niño forming were significantly lower. However, they stressed on the uncertainty that the El Niño–Southern Oscillation could be in a warm-neutral phase or weak El Niño conditions by the peak of the season. On the same day, the United Kingdom Met Office (UKMO) released its forecast of a very slightly above-average season. It predicted 13 named storms, with a 70% chance that the number would be in the range between 10 and 16, and 8 hurricanes, with a 70% chance that the number would be in the range between 6 and 10. It also predicted an ACE index of 145, with a 70% chance that the index would be between 92 and 198. On July 4, TSR released their fourth forecast for the season, increasing their predicted numbers to 17 named storms, 7 hurricanes, and 3 major hurricanes, due to the fact that El Niño conditions would no longer develop by the peak of the season and the warming of sea-surface temperatures across the basin. Additionally, they predicted a revised ACE index of 116 units. During August 9, NOAA released their final outlook for the season, raising their predictions to 14–19 named storms, though retaining 5–9 hurricanes and 2–5 major hurricanes. They also stated that the season had the potential to be extremely active, possibly the most active since 2010.
The Atlantic hurricane season officially began on June 1, 2017. Among the busiest on record, the season produced eighteen tropical depressions, all but one of which further intensified into tropical storms. Ten hurricanes occurred in succession, the greatest number of consecutive hurricanes since the start of the satellite era in 1966. Six of the ten hurricanes further strengthened into major hurricanes. Unlike the pattern of previous years that acted to steer many tropical cyclones harmlessly into the open Atlantic, 2017 featured a pattern conducive for landfalls; in fact, the season culminated into 23 separate landfalls by Atlantic named storms. Hundreds, if not over a thousand deaths were recorded while total damage reached over $250 billion, cementing the 2017 season as the costliest in recorded history.
The hyperactive season came to fruition through a multitude of different factors. Pre-season projections noted the potential for a weak to moderate El Niño event to evolve through the summer and fall on the basis of statistical model guidance; these forecasts were proven to be over-amplified as a result of a phenomenon known as the spring predictability barrier. Instead, equatorial Pacific Ocean temperatures began cooling throughout the summer, reaching La Niña threshold in November and curtailing the negative effects on Atlantic hurricane activity originally expected. In addition, tropical Atlantic Ocean temperatures — previously below average in months prior to the start of the season — underwent rapid warming by late May, providing lower sea level pressures, weaker trade winds, increased mid-level moisture, and all-around a more conducive environment for above average activity.
The season's first tropical cyclone, Arlene, developed on April 19 and became only the second tropical storm on record during the month. Above-average activity continued throughout June and July with the formations of tropical storms Bret, Cindy, Don, Emily, and an unnamed tropical depression; however, a majority of these storms were weak and short-lived. August yielded four storms – Franklin, Gert, Harvey, and Irma – all of which intensified into hurricanes. Harvey attained Category 4 status prior to reaching the Texas coastline, ending the record streak of 4,323 days without a major hurricane landfall in the United States; with damage estimates up to $125 billion, Harvey is tied with Hurricane Katrina as the costliest natural disaster on record in the United States. Hurricane Irma reached peak winds of 185 mph (295 km/h), making it the strongest tropical cyclone outside the Gulf of Mexico and Caribbean Sea. It maintained this strength for 37 consecutive hours, the longest stretch at such an intensity of any storm in recorded history. Irma ravaged the northern Leeward Islands and produced a trail of destruction through the Greater Antilles and Southeast United States.
September featured copious activity, with four hurricanes forming, Jose, Katia, Lee, and Maria, the final of which became the tenth most intense Atlantic hurricane on record. As Irma also persisted into September and reached Category 5 intensity, it and Maria marked the first recorded instance of two Category 5 hurricanes occurring in the same month. Maria caused a major humanitarian crisis in Puerto Rico, resulting in over $100 billion in damage and a death toll that may exceed 1,000. October featured hurricanes Nate and Ophelia, as well as Tropical Storm Philippe; Ophelia became the easternmost major hurricane on record in the Atlantic. Activity concluded with the formation of Tropical Storm Rina in early November, though the season did not officially end until November 30.
Seasonal activity was reflected with an Accumulated Cyclone Energy index value of 223.2675 units,[nb 2] the seventh highest value on record in the Atlantic. ACE is, broadly speaking, a measure of the power of a hurricane multiplied by the length of time it existed; therefore, long-lived storms and particularly strong systems result in high levels of ACE. The measure is calculated at full advisories for cyclones at tropical storm strength—storms with winds in excess of 39 mph (63 km/h). Despite an above average number of storms to begin 2017, many were weak and short-lived, resulting in the lowest ACE value for a season's first five named storms on record. However, Hurricane Irma in August produced the third highest ACE value on record, 66.6 units. The season ultimately featured three storms that produced an ACE value above 40 units, the first occurrence on record. September 2017 featured more ACE than any month in recorded history in the Atlantic (surpassing September 2004), and September 8 alone produced more ACE than any other day on record. Overall, September's ACE value represented activity about three and a half times more active than the 1981–2010 average for the month.
|Tropical storm (SSHWS)|
|Duration||April 19 – April 21|
|Peak intensity||50 mph (85 km/h) (1-min) 990 mbar (hPa)|
A potent extratropical cyclone formed well east of Bermuda on April 16. The cyclone moved southeast, becoming disconnected from the surrounding environment and gradually losing its frontal characteristics. Deep convection formed in bands north and east of the center by 00:00 UTC on April 19, leading to the formation of a subtropical depression. Despite an unfavorable environment, with ocean temperatures near 20 °C (68 °F) and moderate wind shear, convection coalesced near the center and allowed the subtropical depression to become fully tropical by 00:00 UTC on April 20. It intensified into Tropical Storm Arlene six hours later. After attaining peak winds of 50 mph (85 km/h), the storm began to rotate around a larger extratropical low. The storm tracked into the cold sector of the cyclone, causing Arlene to lose tropical characteristics around 12:00 UTC on April 21. The post-tropical cyclone moved south and east, before dissipating well west-southwest of the Azores on April 22.
Upon its formation as a subtropical depression on April 19, Arlene was the sixth known subtropical or tropical cyclone to form in the month of April in the Atlantic basin; the other instances were Ana in 2003, a subtropical storm in April 1992, and three tropical depressions in 1912, 1915, and 1973, respectively. When Arlene became a tropical storm on April 20, this marked only the second such occurrence on record, after Ana in 2003.[nb 3] Furthermore, it had the lowest central pressure of any Atlantic storm recorded in the month of April, with a central pressure of 990 mbar (hPa; 29.23 inHg), again surpassing Ana. Additionally, unrelated to Arlene, Tropical Storm Adrian in the Eastern Pacific basin also formed before the corresponding hurricane season was set to officially begin, being the earliest named storm in the Eastern Pacific proper. This makes 2017 the second consecutive year after 2016 where the first storms in both basins were pre-season storms.
|Tropical storm (SSHWS)|
|Duration||June 19 – June 20|
|Peak intensity||45 mph (75 km/h) (1-min) 1007 mbar (hPa)|
A tropical wave moved off the coast of Africa on June 13 and was first monitored by the National Hurricane Center shortly afterwards. Development, however, was expected to be slow due to its low latitude and relatively fast motion. As it moved swiftly across the Main Development Region of the Atlantic Ocean, the disturbance began to gradually organize, and the NHC raised development chances slightly on June 16. Little change in organization occurred until June 18, at which point a burst of convection near the center of the disturbance prompted the NHC to designate the system as Potential Tropical Cyclone Two at 21:00 UTC. This was the agency's first designation of a disturbance that had not yet developed into a tropical cyclone. The storm continued to organize as it accelerated towards Venezuela and Trinidad and Tobago throughout the night, with banding features becoming evident. Later on June 19, the system developed a closed low-level circulation and was upgraded to Tropical Storm Bret at 21:00 UTC. One day later, at 21:00 UTC on June 20, the last advisory on Bret was issued following its degeneration into a tropical wave. The remnants later contributed to the formation of Hurricane Dora in the eastern Pacific.
According to Phil Klotzbach of Colorado State University, Bret was the earliest storm to form in the Main Development Region on record, surpassing a record set by Tropical Storm Ana in 1979. Bret was also the lowest latitude named storm in the month of June since 1933 at 9.4°N. In Trinidad, one person died after he slipped and fell while running across a makeshift bridge; the fatality is considered indirectly related to Bret. In Tobago, a man's house collapsed on him; he eventually succumbed to his injuries a week later.
|Tropical storm (SSHWS)|
|Duration||June 20 – June 23|
|Peak intensity||60 mph (95 km/h) (1-min) 991 mbar (hPa)|
The NHC first began monitoring the potential for tropical cyclone formation over the northwestern Caribbean Sea on June 13. A large area of disturbed weather developed within the region three days later, and it slowly organized while entering the central Gulf of Mexico, prompting the NHC to begin advisories on a potential tropical cyclone on June 19. The structure of the system was initially sprawling, with tropical storm-force winds well displaced from a broad area of low pressure with embedded swirls. A reconnaissance aircraft investigating the system around 18:00 UTC the following day was able to pinpoint a well-defined center, indicating the formation of Tropical Storm Cindy. Despite the presence of dry air and strong wind shear, the cyclone still managed to attain peak winds of 60 mph (95 km/h) before weakening on approach to the Louisiana coastline. It made landfall between Port Arthur, Texas and Cameron, Louisiana early on June 22 being the first tropical cyclone to make landfall in Louisiana since Hurricane Isaac of 2012. Cindy weakened while progressing inland and transitioned to a post-tropical cyclone on June 23.
A state of emergency was declared for Biloxi, Mississippi in anticipation of flooding. A ten-year-old boy died from injuries sustained during the storm in Fort Morgan, Alabama. A second fatality later occurred in Bolivar Peninsula, Texas.
|Tropical depression (SSHWS)|
|Duration||July 5 – July 7|
|Peak intensity||30 mph (45 km/h) (1-min) 1009 mbar (hPa)|
Early on June 29, the NHC began tracking a tropical wave embedded within a large envelope of deep moisture across the coastline of western Africa. The disturbance was introduced as a potential contender for tropical cyclone formation two days later, as environmental conditions were expected to favor slow organization. It began to show signs of organization over the central Atlantic early on July 3, but the chances for development began to decrease two days later as the system moved toward a more stable environment. Having already acquired a well-defined circulation, the development of a persistent mass of deep convection around 03:00 UTC the following day prompted the NHC to upgrade the wave to Tropical Depression Four, located about 1,545 miles (2,485 km) east of the Lesser Antilles. Despite wind shear being low, the nascent depression struggled to intensify due to a dry environment caused by a Saharan Air Layer to its east, causing the low-level circulation to weaken, and resulting in the tropical depression degenerating into an open tropical wave late on the next day.
|Tropical storm (SSHWS)|
|Duration||July 17 – July 18|
|Peak intensity||50 mph (85 km/h) (1-min) 1005 mbar (hPa)|
Late on July 15, the NHC highlighted a low-pressure trough over the central Atlantic as having the potential to develop into a tropical cyclone in the coming days. The disturbance began to show signs of organization early on July 17, and a tropical depression formed at 06:00 UTC that day. The system continued to intensify, and developed into Tropical Storm Don just six hours later. The storm's overall appearance improved over subsequent hours up until around 00:00 UTC, as a central dense overcast, accompanied by significant clusters of lightning, became pronounced. Don attained its peak intensity at this time, characterized by winds of approximately 50 mph (85 km/h) as measured by reconnaissance aircraft. The next plane to investigate the cyclone a few hours later, however, found that the system's center had become less defined, and that sustained wind speeds had decreased to about 40 mph (65 km/h). A combination of reconnaissance data and surface observations from the Windward Islands indicated that Don opened up into a tropical wave around 12:00 UTC on July 18, as it entered the eastern Caribbean Sea.
|Tropical storm (SSHWS)|
|Duration||July 31 – August 2|
|Peak intensity||45 mph (75 km/h) (1-min) 1005 mbar (hPa)|
In late July, a dissipating cold front extended into the northeastern Gulf of Mexico, where the NHC began forecasting the development of an area of low pressure over the next day on July 30. Any development was expected to be slow due to land proximity and marginal upper-level winds. Contrary to predictions, a rapid period of organization occurred over the next 24 hours and the system was deemed as Tropical Depression Six at 09:00 UTC on July 31, strengthening into Tropical Storm Emily just two hours later. After attaining its peak intensity with winds of 45 mph (75 km/h) and a minimum pressure of 1,005 mbar (29.7 inHg), Emily made landfall on Anna Maria Island around 14:45 UTC. Weakening quickly ensued, and later that day the circulation of Emily became elongated as it was downgraded to a tropical depression. The increasingly disrupted system later moved off the First Coast of Florida into the western Atlantic early the next day, accelerating northeastwards before becoming embedded within a frontal zone early on August 2.
Following the classification of Tropical Storm Emily, Florida Governor Rick Scott declared a state of emergency for 31 counties to ensure residents were provided with the necessary resources. The storm spawned an EF0 tornado near Bradenton. The tornado was on the ground for about 1.3 mi (2.1 km) and destroyed two barns and a few greenhouses, while an engineered wall collapsed, leaving about $96,000 in damage. On August 1, torrential rains related to Emily impacted parts of Miami Beach, with accumulations reaching 6.97 in (177 mm) in 3.5 hours, of which 2.17 in (55 mm) fell in just 30 minutes. Coinciding with high tide the deluge overwhelmed flood pumps, with three of them shutting down due to lightning-induced power outages, and resulted in significant flash floods. Multiple buildings suffered water damage, with some having 2.5 ft (0.76 m) of standing water. One person was hospitalized after becoming stuck in flood waters. Portions of Downtown Miami, such as Brickell, were also heavily affected; numerous vehicles became stranded in flooded roadways. Total damages from Emily are estimated to be less than US$10 million.
|Category 1 hurricane (SSHWS)|
|Duration||August 7 – August 10|
|Peak intensity||85 mph (140 km/h) (1-min) 981 mbar (hPa)|
The NHC began tracking a tropical wave in the southeastern Caribbean Sea for possible development on August 3. After organizing for a few days, advisories were initiated on Potential Tropical Cyclone Seven at 21:00 UTC on August 6. The disturbance became Tropical Storm Franklin at 03:00 UTC on August 7. After strengthening into a moderate tropical storm, Franklin made its first landfall near Pulticub, Mexico at 03:00 UTC on August 8. The cyclone weakened considerably while over the peninsula, however its satellite presentation remained well-defined, with the inner core tightening up considerably. Later that day, Franklin emerged into the Bay of Campeche, and immediately began strengthening again, becoming a hurricane late on August 9. Five hours after peaking in intensity with winds of 85 mph (140 km/h) and a pressure of 981 mbar (28.97 inHg), Franklin made landfall in Lechuguillas, Mexico, and thereafter began to rapidly weaken. By 15:00 UTC on August 10, Franklin had dissipated as a tropical cyclone. However, its mid-level circulation remained intact and later contributed to the formation of Tropical Storm Jova in the Eastern Pacific early on August 12.
Immediately upon classification of Franklin as a potential tropical cyclone, tropical storm warnings were issued for much of the eastern side of the Yucatán Peninsula on August 6; a small portion of the coastline was upgraded to a hurricane watch with the possibility of Franklin nearing hurricane intensity as it approached the coastline the next night. Approximately 330 people were reported as going into storm shelters, and around 2,200 relocated from the islands near the coastline to farther inland in advance of the storm. In the Mexican part of the peninsula, damage was reported as having being minimal, mainly in Belize as the storm tracked slightly more northwards then expected, lessening impacts. Nonetheless, some areas received up to a foot of rain.
|Category 2 hurricane (SSHWS)|
|Duration||August 13 – August 17|
|Peak intensity||105 mph (165 km/h) (1-min) 967 mbar (hPa)|
On August 2, the NHC began monitoring a tropical wave and its associated convection over the western coast of Africa. As the disturbance tracked west-northwest, its structure changed little in organization, but environmental conditions were expected to support the formation of a tropical cyclone. Instead, the system remained poorly defined and entered a less conducive environment east of the Leeward Islands. After progressing into the southwestern Atlantic several days later, the wave encountered more favorable upper-level winds and began to show signs of organization. Following the formation of a well-defined circulation, the disturbance was upgraded to a tropical depression at 03:00 UTC on August 13; by 21:00 UTC that afternoon, it intensified into Tropical Storm Gert. At 03:00 UTC on August 15, Gert intensified to a Category 1 hurricane with maximum sustained winds of 75 mph (120 km/h), making it the second hurricane of the season. Accelerating east-northeastwards, Gert peaked as a Category 2 system early on August 17 at an unusually high latitude of 40°N. Thereafter, Gert began to rapidly weaken as it shifted from the Gulf Stream over cooler waters. Just 12 hours after achieving peak intensity, Gert weakened below hurricane status and evolved to an extratropical cyclone well east of Nova Scotia.
|Category 4 hurricane (SSHWS)|
|Duration||August 17 – September 1|
|Peak intensity||130 mph (215 km/h) (1-min) 937 mbar (hPa)|
The NHC began monitoring an area of low pressure southwest of Cape Verde on August 13, which was expected to merge with a tropical wave that just emerged off the coast of Africa within a few days. Instead the two systems remained separate, with the first low pressure area coalescing into Potential Tropical Cyclone Nine by 15:00 UTC on August 17, and the other system moving farther north, eventually becoming Potential Tropical Cyclone Ten. A reconnaissance aircraft investigating the system was able to locate a well-defined circulation, and the disturbance was upgraded to Tropical Storm Harvey accordingly six hours later. On a westward course into the Caribbean Sea, the storm was plagued by relentless wind shear, and it degenerated to an open tropical wave south of Hispaniola, by 03:00 UTC on August 20. Harvey's remnants continued into the Bay of Campeche, where more conducive environmental conditions led to the re-designation of a tropical depression, around 15:00 UTC on August 23, and subsequent intensification into a tropical storm by 04:00 UTC on the next morning. The tropical cyclone began a period of rapid intensification shortly thereafter, attaining hurricane intensity by 17:00 UTC on August 24, Category 3 strength around 19:00 UTC on August 25, and Category 4 intensity by 23:00 UTC on that day.
Harvey crossed the shore between Port Aransas and Port O'Connor, Texas around 03:00 UTC on August 26, possessing maximum winds of 130 mph (215 km/h). The storm gradually spun down, becoming a tropical storm around 18:00 UTC on August 26, as it meandered across southeastern Texas. A light steering pattern caused the storm to emerge into the Gulf of Mexico on August 28, but a turn toward the north-northeast brought it ashore west of Cameron, Louisiana, as a weak tropical storm around 09:00 UTC on August 30. The system weakened to a tropical depression over central Louisiana late that day before losing tropical characteristics over central Tennessee early on September 1.
Rockport, Fulton, and the surrounding cities bore the brunt of Harvey's eyewall as it moved ashore in Texas. Numerous structures were heavily damaged or destroyed, boats were tossed or capsized, power poles were leant or snapped, and trees were downed. As debris covered roadways and cellphone service was compromised, communication to the hardest-hit locales was severed. One person was killed in Rockport after a fire began in his home, and approximately a dozen people were injured. Farther northeast, dire predictions of potentially catastrophic flooding came to fruition in Houston and nearby locales, where floodwaters submerged major highways, forced residents to their attics and roofs, and overwhelmed emergency lines. The National Weather Service tweeted, "This event is unprecedented & all impacts are unknown & beyond anything experienced..." At least 30 people were killed in the Houston area due to flooding. In addition to the flooding, Harvey spawned several tornadoes around Houston. Estimates place the damage caused by Harvey at $125 billion, which ties it with Hurricane Katrina as the costliest tropical cyclone on record. Harvey killed 91 people, including 90 in the United States and 1 man in Guyana who slipped and fell while he was running across a bridge. The storm produced 60.58 inches (1,538.7 mm) of rainfall in Texas, the highest-ever rainfall total for any tropical cyclone in the United States.
Harvey was the first major hurricane to strike the United States since Hurricane Wilma in 2005, ending the record-length 4,323-day span in which no tropical cyclones made landfall as major hurricanes. It is the most intense tropical cyclone to move ashore the US mainland since Hurricane Charley in 2004, and the first Category 4 hurricane to make landfall in Texas since Hurricane Carla in 1961.
|Category 5 hurricane (SSHWS)|
|Duration||August 30 – September 12|
|Peak intensity||185 mph (295 km/h) (1-min) 914 mbar (hPa)|
A westward-moving tropical wave, first monitored over western Africa on August 26, organized into Tropical Storm Irma around 15:00 UTC on August 30. Amid an environment of low wind shear and warm ocean temperatures, the newly formed cyclone moved generally westward while intensifying. A reconnaissance aircraft investigating the system east of the Caribbean on September 5 found the cyclone at Category 5 intensity. With a clear eye surrounded by a ring of extremely deep convection, Irma attained its peak intensity with winds of 185 mph (295 km/h) later that day, and maintained this intensity as it moved through the northern Leeward Islands. Some weakening occurred south of the Bahamas, but the cyclone regained Category 5 intensity before making landfall on the Sabana-Camagüey Archipelago of Cuba around 03:00 UTC on September 9. Land interaction disrupted the storm temporarily, but once again it strengthened to acquire winds of 130 mph (215 km/h), before making landfall in Cudjoe Key of the Florida Keys early on September 10. A few hours later, it struck Marco Island, Florida, with winds of 115 mph (185 km/h). Irma continued north and west, steadily weakening over the Southeastern United States before losing tropical characteristics in Georgia, early on September 12.
With peak winds of 185 mph (295 km/h), Irma was the strongest Atlantic storm outside of the Gulf of Mexico or Caribbean Sea on record. Maintaining peak intensity for 37 consecutive hours, Irma is the only tropical cyclone on record worldwide to have had winds that intense for so long. As the storm moved through the northern Leeward Islands, it became the only Category 5 hurricane to make a direct impact there; its landfall intensity ties it with the 1935 Labor Day hurricane as the strongest landfalling cyclone on record in the Atlantic. Two Category 4 hurricanes, Harvey and Irma, struck the continental United States in the span of two weeks; this marks the first time the country has suffered two landfalls of such intensity during the same hurricane season, in recorded history. Lastly, Irma acquired the third-highest Accumulated Cyclone Energy index on record in the Atlantic, behind only the 1899 San Ciriaco hurricane and Hurricane Ivan of 2004.
In the aftermath of Irma, development on the islands of Barbuda and Saint Martin was described as being "95% destroyed" by respective political leaders, with 1,400 people feared homeless in Barbuda. So far, Irma has resulted in at least 144 deaths, including 100 in the United States and 44 across the Caribbean.
|Category 4 hurricane (SSHWS)|
|Duration||September 5 – September 22|
|Peak intensity||155 mph (250 km/h) (1-min) 938 mbar (hPa)|
A westward-moving tropical wave exited the west coast of Africa on August 31, organizing into Tropical Storm Jose over the open eastern Atlantic by 15:00 UTC on September 5. The quickly-strengthening cyclone attained hurricane intensity late on September 6, reached major hurricane strength late on September 7, and ultimately peaked as a high-end Category 4 hurricane with winds of 155 mph (250 km/h) early on September 9. Moderate wind shear weakened the cyclone as it conducted a slow clockwise loop between Bermuda and the Caribbean Sea and eventually moved north ahead of an approaching trough. Steering currents collapsed by early on September 21, causing the system to stall offshore the Northeastern United States as a weakening tropical storm. With a rain shield in the northern and northwestern semicircles accompanied by a lack of deep convection over the center, the NHC declared Jose a post-tropical cyclone around 03:00 UTC on September 22, ending advisories once the storm's tropical storm-force winds moved off the New England coast at 21:00 UTC.
The government of Antigua and Barbuda began efforts on September 8 to evacuate the entire island of Barbuda prior to Jose's anticipated arrival, as most structures on the island had been heavily damaged or destroyed by Hurricane Irma.
|Category 2 hurricane (SSHWS)|
|Duration||September 5 – September 9|
|Peak intensity||105 mph (165 km/h) (1-min) 972 mbar (hPa)|
A trough was present over the southwestern Gulf of Mexico on September 3, producing a widespread area of thunderstorms. Two days later, a distinct low pressure area formed about 50 mi (80 km) east of Tampico, Tamaulipas. At 21:00 UTC that day, the NHC designated the system as Tropical Depression Thirteen after an organized area of convection formed over the center. Located in an area of weak steering currents, the depression drifted slowly eastward. With gradually decreasing wind shear and warm water temperatures, the system intensified into Tropical Storm Katia on September 6, as the convection became better organized. Later that day, an aircraft reconnaissance flight into the storm found a partial eye wall and surface winds of 76 mph (122 km/h); on that basis, the NHC upgraded Katia to hurricane status. The convection organized into a central dense overcast as the system stalled. Late in the evening of September 8, Katia made landfall north of Tecolutla, Mexico as a weak Category 1 storm. The system rapidly dissipated over land on September 9. Katia's remnants traveled across Central America and later emerged over the Pacific Ocean, where redevelopment ensued. Tropical Depression Fifteen-E formed, which later strengthened into Hurricane Otis about a week later.
In preparation for Katia, over 4,000 residents were evacuated from the states of Veracruz and Puebla. Tourists left coastal towns, emergency shelters were opened, and storm drains were cleared before the onset of heavy rainfall. Two fatalities were reported in Xalapa from mudslides, while a third man was swept away by floodwaters in Jalcomulco. States of emergency were declared for 40 out of a total 53 municipalities that reported minor damage from mudslides and flooding. About 77,000 residents were left without power at the height of the storm.
|Category 3 hurricane (SSHWS)|
|Duration||September 15 – September 30|
|Peak intensity||115 mph (185 km/h) (1-min) 962 mbar (hPa)|
A tropical wave moved off the coast of Africa on September 13. Contrary to predictions of only gradual organization over the following days, the system rapidly organized, becoming Tropical Depression Fourteen at 03:00 UTC on September 15. The NHC upgraded the system to Tropical Storm Lee at 15:00 UTC on the next day, based on an increase in deep convection and an advanced scatterometer (ASCAT) pass which indicated that it was producing minimal tropical-storm-force winds. After encountering wind shear, Lee gradually weakened into a tropical depression early on September 17 before degenerating into a remnant low two days later. The NHC monitored the remnants of Lee intermittently for several days, but regeneration was not considered likely. However, the mid-level remnants of the tropical cyclone became intertwined with an upper-level trough; a deep burst of convection led to a new surface circulation, and by 21:00 UTC on September 22, the system reorganized into Tropical Depression Lee. Lee intensified into a tropical storm six hours later.
A compact tropical cyclone, Lee organized, as small curved bands wrapped into a small cluster of central convection. A microwave pass around 21:00 UTC on September 23 indicated the formation of a ring of shallow to moderate convection around the center, often a harbinger of rapid intensification. Indeed, by 06:30 UTC the next morning, the presence of an eye on satellite imagery prompted the NHC to abruptly upgrade Lee to a hurricane as it moved erratically. After attaining winds of 90 mph (150 km/h), the storm weakened slightly due to moderate southeasterly wind shear. By 09:00 UTC on September 26, however, the storm attained Category 2 strength. An eyewall replacement cycle that night led to the emergence of a larger eye surrounded by cold cloud tops, and by 15:00 UTC on September 27, Lee attained its peak as a Category 3 hurricane with winds of 115 mph (185 km/h). The system recurved northeast after peak intensity and quickly succumbed to strong northerly wind shear and progressively cooler ocean waters; it weakened below major hurricane strength by 03:00 UTC on September 28, fell below hurricane strength by 15:00 UTC on September 29, and degenerated to a post-tropical cyclone by 09:00 UTC on September 30, after lacking deep convection for over 12 hours. On October 1, Lee's remnant was absorbed by another extratropical cyclone to the north.
|Category 5 hurricane (SSHWS)|
|Duration||September 16 – September 30|
|Peak intensity||175 mph (280 km/h) (1-min) 908 mbar (hPa)|
On September 13, the NHC began monitoring a tropical wave southwest of Cape Verde. The disturbance moved west, organizing into a potential tropical cyclone at 15:00 UTC on September 16 and Tropical Storm Maria six hours later. On a west-northwest course, Maria intensified at an exceptional rate; over a 24-hour period ending at 23:45 UTC on September 18, Maria doubled its winds from 80 mph (130 km/h) to 160 mph (260 km/h), thus reaching Category 5 strength. After striking Dominica at that intensity a little over an hour later, the storm weakened slightly as it entered the eastern Caribbean Sea; amid favorable conditions, however, Maria regained Category 5 intensity and eventually reached peak winds of 175 mph (280 km/h) late on September 19. Around 08:00 UTC on September 20, the eyewall of Maria struck Vieques, and a little over two hours later, the core of the storm made landfall near Yabucoa, Puerto Rico, with winds of 155 mph (250 km/h). Land interaction caused a significant degration in Maria's structure, and it weakened to a Category 2 hurricane while moving offshore. Growing in size and curving north, Maria regained Category 3 strength and maintained this intensity for several days before entering a less conducive environment. After fluctuating between tropical storm and minimal hurricane strength off the coastline of North Carolina, the system turned sharply east away from the United States, and ultimately evolved into an extratropical cyclone over the far northern Atlantic, on September 30.
Dominica sustained catastrophic damage from Maria, with nearly every structure on the island damaged or destroyed. Surrounding islands were also dealt a devastating blow, with reports of flooding, downed trees, and damaged buildings. Puerto Rico also suffered catastrophic damage. The island's electric grid was devastated, leaving all 3.4 million residents without power. Many structures were leveled, while floodwaters trapped thousands of citizens. The United States National Guard, Coast Guard, Army Corps of Engineers, and other like units worked to administer aid and assist in search and rescue operations. However, the U.S. federal government response was criticized for its delay in waiving the Jones Act, a statute which prevented Puerto Rico from receiving aid on ships from non-U.S. flagged vessels. Along the coastline of the United States, tropical storm-force gusts cut power to hundreds of citizens; rip currents offshore led to three deaths and numerous water rescues. Estimates of damage from Maria range from $15.9 billion by Estudios Técnicos to $95 billion by Moody's Analytics. Most of the damage occurred in Puerto Rico; Ricardo Rosselló, the governor of Puerto Rico, believes the storm caused $90 billion in damages. The official death toll currently stands at 112, with: 71 killed in the United States, consisting of 64 in Puerto Rico, 4 in the contiguous United States, and 3 in the United States Virgin Islands; 31 in Dominica; 5 in the Dominican Republic; 3 in Haiti; and 2 in Guadeloupe. While Maria's official death toll in Puerto Rico is currently 64, a statistically significant spike in monthly fatalities (more than 1,000 deaths compared to previous years) across Puerto Rico exists in the two months following the hurricane.
|Category 1 hurricane (SSHWS)|
|Duration||October 4 – October 9|
|Peak intensity||90 mph (150 km/h) (1-min) 981 mbar (hPa)|
On October 3, a broad area of low pressure formed in the southwestern Caribbean Sea. The disturbance quickly organized, and on October 4, the NHC announced that the disturbance had strengthened into Tropical Depression Sixteen, and began issuing advisories on the storm. The system slowly became stronger and more organized, and, early on October 5, was deemed a tropical storm and named Nate. Nate's first U.S landfall was in the mouth of the Mississippi River as a Category 1 hurricane, and Nate's second U.S landfall was at 12:30 a.m. CST near Biloxi, MS, both on October 8. After Nate tracked inland, it quickly weakened into a tropical depression, and a few hours later, evolved into an extratropical storm. Hurricane Nate also broke the record for the fastest moving hurricane ever recorded in the Gulf of Mexico.
Nate caused at least 45 deaths, including 16 in Nicaragua, 11 in Costa Rica, 7 in Panama, 3 in Honduras, 2 in the United States, and 1 in El Salvador., 5 in Guatemala, and a further 9 missing accumulative of all affected areas.
|Category 3 hurricane (SSHWS)|
|Duration||October 9 – October 16|
|Peak intensity||115 mph (185 km/h) (1-min) 960 mbar (hPa)|
On October 6, a circulation developed at the end of a cold front in the northeast Atlantic, with a low pressure area developing within the circulation on the same day. While the low drifted slowly to the northeast, it began to lose its frontal system and acquire subtropical characteristics by October 7. The next day, the storm encountered stronger wind shear, removing some of its convection, and slightly weakening the system; however, the storm eventually grew better organized and developed more convection around its low pressure center later in the day. Early on October 9, the system fully transitioned into a tropical cyclone, prompting the NHC to begin issuing advisories on Tropical Depression Seventeen. The tropical depression continued to strengthen, becoming Tropical Storm Ophelia later that day. Ophelia continued to strengthen due to low wind shear and on October 11, the National Hurricane Center upgraded it to a hurricane, making it the tenth consecutive storm this season to reach hurricane strength. Ophelia became a Category 2 hurricane on October 12 at 5:00 p.m. AST (21:00 UTC). On October 14 at 11:00 a.m. AST (15:00 UTC), Ophelia unexpectedly intensified to a Category 3 hurricane, making Ophelia the sixth major hurricane of the season and the easternmost storm of such strength in the Atlantic basin on record. On October 15, Ophelia began to weaken, while accelerating northeastward towards Ireland and Great Britain, with the storm's wind field also expanding. Early on October 16, Ophelia transitioned into a hurricane-strength extratropical cyclone, as it began impacting Ireland and Britain.
In County Waterford, a woman was killed when a tree fell on her car, caused by the winds from Ophelia's remnants. In County Tipperary, a man was killed while clearing a fallen tree with a chainsaw. Another person was killed in Dundalk when a tree fell on his car. Two other men died after suffering fatal injuries while carrying out repairs to damage caused by Ophelia and Storm Brian. Hurricane Ophelia also fanned wildfires in Portugal and Spain, killing 49 people.
|Tropical storm (SSHWS)|
|Duration||October 28 – October 29|
|Peak intensity||40 mph (65 km/h) (1-min) 1000 mbar (hPa)|
On October 22, the NHC forecasted that a broad area of low pressure would form in the southwestern Caribbean Sea. On October 23, as predicted, a broad low formed off of the northwestern coast of Nicaragua. However, the system remained disorganized for the next several days until the afternoon of October 27, when it quickly organized, prompting the NHC to upgrade the system into Potential Tropical Cyclone Eighteen, since it lacked a well-defined center. Over the next day, gradual organization occurred until the system coalesced into a tropical depression at 12:00 UTC on October 28; it strengthened into Tropical Storm Philippe six hours later. Strong wind shear and land interaction quickly began to cause the system to become disorganized, and Philippe made landfall near Cuba's Zapata Peninsula as a very disorganized tropical storm with winds of 40 mph (65 km/h). It dissipated hours later – although operationally, Philippe was assessed as crossing the Florida Keys and exiting into the western Atlantic Ocean, which was later attributed in post-analysis to a non-tropical area of low pressure that was interacting with Philippe, shortly before it dissipated.
|Tropical storm (SSHWS)|
|Duration||November 5 – November 9|
|Peak intensity||60 mph (95 km/h) (1-min) 991 mbar (hPa)|
In early November, the National Hurricane Center began to monitor a non-tropical area of low pressure in the central Atlantic, which had formed at the end of a decaying cold front, for potential tropical development. Gradually, the system became better organized and was able to maintain an area of deep convection to the east of the center. On the morning of November 6, the NHC declared that Tropical Depression Nineteen had formed in the Central Atlantic. As the day progressed, wind shear from the west began to impact the tropical cyclone, displacing shower and thunderstorm activity to the east. Despite this, the system continued to strengthen, and by 03:00 UTC on November 7, the tropical depression was upgraded to a tropical storm, gaining the name Rina. As it headed on a northerly track, Rina continued to strengthen despite strong shear and dry air intrusion, and also began to show subtropical characteristics marked by most of the deep convection and strongest winds well removed from the center. Nonetheless, Rina strengthened into a strong tropical storm with peak winds of 60 mph (95 km/h). Shortly after attaining peak strength, convection began to wane and became displaced well from the center of the system, and the storm began to show a comma-like appearance on satellite imagery, signifying an extratropical transition. The storm began to accelerate to the north ahead of an approaching cold front and was absorbed into the frontal system around 15:00 UTC on November 9, a few hundred miles to the northeast of Newfoundland.
With the formation of Rina in November, the 2017 season became the first since 2013 to feature a named storm in every month within the official bounds of the Atlantic hurricane season (June through November).
The NHC began monitoring a tropical wave that just emerged off the coast of Africa on August 13, which was expected to merge with an area of low pressure southwest of Cape Verde within a few days. Instead the two systems remained separate, with the first eventually coalescing into Potential Tropical Cyclone Ten on August 27 northeast of Florida and the other low pressure eventually becoming Hurricane Harvey. The NHC gave this disturbance a 90% chance of becoming a tropical cyclone within the next 48 hours. After attaining winds of 45 mph (70 km/h), the system subsequently began to undergo an extratropical transition. Consequently, the NHC issued its last advisory on the system at 21:00 UTC on August 29, declaring the system to be an extratropical low. However, after the storm became extratropical, it strengthened, peaking at 80 mph maximum sustained winds, before being absorbed by a larger extratropical system, Windstorm Perryman.
The following list of names was used for named storms that formed in the North Atlantic in 2017. Any retired names will be announced by the World Meteorological Organization (WMO) during the 40th session of the Regional Association Hurricane Committee, which will take place in Martinique from April 9–13 in 2018. The names not retired from this list will be used again in the 2023 season. This is the same list used in the 2011 season, with the exception of the name Irma, which replaced Irene; Irma was previously used in 1978.
The usage of the name "Don" in July garnered some attention relating to United States President Donald Trump. Max Mayfield, former director of the National Hurricane Center, clarified that the name had no relation to Trump and was chosen in 2006 as a replacement for Dennis. Regardless, some outlets such as the Associated Press, "poked fun" at the name and Trump.
This is a table of all the storms that formed in the 2017 Atlantic hurricane season, besides Potential Tropical Cyclone Ten. It includes their duration, names, affected areas, damages, and death totals. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but were still related to that storm. Damage and deaths include totals while the storm was extratropical, a wave, or a low, and all the damage figures are in 2017 USD.
|Saffir–Simpson hurricane wind scale|
|Dates active||Storm category
at peak intensity
|Arlene||April 19 – 21||Tropical storm||50 (85)||990||None||None||None|
|Bret||June 19 – 20||Tropical storm||45 (75)||1007||Guyana, Venezuela, Trinidad and Tobago, Windward Islands||> $3 million||1 (1)|
|Cindy||June 20 – 23||Tropical storm||60 (95)||991||Honduras, Belize, Cayman Islands, Yucatán Peninsula, Cuba, Southern United States, Eastern United States||$25 million||2 (1)|
|Four||July 5 – 7||Tropical depression||30 (45)||1009||None||None||None|
|Don||July 17 – 18||Tropical storm||50 (85)||1005||Windward Islands, Barbados, Grenada, Trinidad and Tobago||None||None|
|Emily||July 31 – August 2||Tropical storm||45 (75)||1005||Florida||$10 million||None|
|Franklin||August 7 – 10||Category 1 hurricane||85 (140)||981||Nicaragua, Honduras, Guatemala, Belize, Yucatán Peninsula, Central Mexico||$15 million||None|
|Gert||August 13 – 17||Category 2 hurricane||105 (165)||967||Bermuda, East Coast of the United States, Atlantic Canada||None||0 (2)|
|Harvey||August 17 – September 1||Category 4 hurricane||130 (215)||937||Barbados, Suriname, Guyana, Windward Islands, Nicaragua, Belize, Yucatán Peninsula, Northeastern Mexico, Southern United States (Texas, Louisiana), Eastern United States||$125 billion||69 (39)|
|Irma||August 30 – September 12||Category 5 hurricane||185 (295)||914||Cape Verde, Leeward Islands (Barbuda, Saint Martin, Saint Barthelemy, U.S. Virgin Islands), Puerto Rico, Hispaniola, Turks and Caicos Islands, The Bahamas, Cuba, Southeastern United States (Florida and Georgia), Northeastern United States||≥ $64.76 billion||66 (81)|
|Jose||September 5 – 22||Category 4 hurricane||155 (250)||938||Leeward Islands, East Coast of the United States||$2.8 million||0 (1)|
|Katia||September 5 – 9||Category 2 hurricane||105 (165)||972||Eastern Mexico||Unknown||3 (0)|
|Lee||September 15 – 30||Category 3 hurricane||115 (185)||962||Cabo Verde||Minimal||None|
|Maria||September 16 – 30||Category 5 hurricane||175 (280)||908||Lesser Antilles (Dominica, Guadeloupe, Martinique, Saint Croix), Puerto Rico, Hispaniola, Turks and Caicos Islands, The Bahamas, Southeastern United States, Mid-Atlantic States, United Kingdom, Ireland, France, Spain||≥ $91.61 billion||112–1,133|
|Nate||October 4 – 9||Category 1 hurricane||90 (150)||981||Nicaragua, Honduras, Costa Rica, El Salvador, Panama, Mexico, Cayman Islands, Cuba, Southeastern United States (Louisiana, Alabama, Mississippi, and Florida Panhandle), Northeastern United States, Atlantic Canada||$207.3 million||43 (2)|
|Ophelia||October 9 – 16||Category 3 hurricane||115 (185)||960||Azores, Portugal, Spain, France, Ireland, United Kingdom, Norway, Sweden, Finland, Estonia, Russia||> $71 million||3 (51)|
|Philippe||October 28 – 29||Tropical storm||40 (65)||1000||Central America, Cayman Islands, Yucatán Peninsula, Cuba, Florida||Minimal||None|
|Rina||November 5 – 9||Tropical storm||60 (95)||991||None||None||None|
|18 systems||April 19 –
|185 (295)||908||≥ $281.14 billion||299 – 1,320 (178)|