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Top-10 Most Extreme Atlantic Hurricane Seasons in the Satellite Era
Published: June 12, 2018
Atlantic hurricane seasons since the satellite era began in the mid-1960s have had as many as 28 named storms and as few as four. Various factors in the atmosphere and the ocean typically drive whether a given hurricane season is busy or rather tame.
But ranking the most extreme hurricane seasons isn't as simple as examining the number of tropical storms and hurricanes that occurred in a given year. We need to dig a little deeper to capture the full picture.
A better way to rank the most extreme seasons is using the ACE (Accumulated Cyclone Energy) index, which is calculated by adding each tropical storm or hurricane's wind speed through its life cycle.
Long-lived, intense hurricanes have a high ACE index while short-lived, weak tropical storms have a low value. The ACE of a season is the sum of the ACE for each storm and takes into account the number, strength and duration of all the tropical storms and hurricanes in the season. A season's ACE value doesn't necessarily reflect the severity of impacts to land in a given season.
Below are the 10 most extreme hurricane seasons based on ACE index data from Colorado State University tropical scientist Dr. Phil Klotzbach. We've only included Atlantic hurricane seasons in the satellite era, which began in 1966, in order to have the most reliable information.
(MORE: Hurricane Central)
- ACE index: 165
- 19 named storms, 12 hurricanes, 5 major hurricanes
- 89.5 named storm days, 38.5 hurricane days, 11 major hurricane days
The 2010 season ties as having the second-most hurricanes for a single season in the top-10. Hurricanes Earl and Igor were two of the more notable and long-lived major hurricanes that season.
Igor was a major hurricane for nearly five days and was the strongest of the season, with maximum sustained winds of 155 mph at its peak. Bermuda and Atlantic Canada were both struck by Igor, and Newfoundland suffered its worst hurricane damage in recent history, the National Hurricane Center said.
Earl was a major hurricane for more than three days and grazed North Carolina's Outer Banks before making landfall in Nova Scotia as a Category 1.
8. (tie) 1996
- ACE index: 166
- 13 named storms, 9 hurricanes, 6 major hurricanes
- 79 named storm days, 45 hurricane days, 13 major hurricane days
Almost half of the 13 named storms in the 1996 season went on to become major hurricanes, vaulting the year to a tie as the eighth-most-extreme season in the satellite era.
Edouard was a major hurricane for an exceptionally long time of nearly eight days, but that occurred well away from land in the open Atlantic Ocean.
North Carolina was struck by Hurricane Fran during the season; it was a Category 3 when it roared ashore near Cape Fear.
8. (tie) 1969
- ACE index: 166
- 18 named storms, 12 hurricanes, 5 major hurricanes
- 92.25 named storm days, 40.25 hurricane days, 6.5 major hurricane days
Camille is the most well-known hurricane from the 1969 season. It reached Category 5 status in the Gulf of Mexico before slamming into the Mississippi coast with maximum sustained winds estimated at 170 to 175 mph.
Another boost to the 1969 season's extreme nature was Inga, which spun through the Atlantic Ocean for nearly 25 days. It still holds the record as the third-longest-lived tropical cyclone in the Atlantic Basin.
- ACE index: 176
- 16 named storms, 7 hurricanes, 3 major hurricanes
- 81.5 named storm days, 32.75 hurricane days, 16.75 major hurricane days
Two of the three major hurricanes in the 2003 season held Category 3 or stronger intensity for a lengthy period of time. That contributed to 16.75 major hurricane days, fourth-most of any season on this list.
Isabel held its major hurricane status for nearly eight days, maxing out as a Category 5 for a total of 1.75 days during that time. Eastern parts of North Carolina and Virginia were pounded by Isabel, which made landfall as a Category 2.
Fabian was the other long-lived major hurricane of the 2003 season and curled through the Atlantic as a Category 3 or stronger for seven days. Bermuda saw extensive damage from Fabian, which passed very close to the archipelago as a Category 3.
- ACE index: 177
- 12 named storms, 8 hurricanes, 5 major hurricanes
- 78.5 named storm days, 41 hurricane days, 14.25 major hurricane days
The 1999 season featured a near-average number of named storms, but a large proportion of those reached hurricane and major hurricane strength.
All five of the major hurricanes in the 1999 season – Bret, Cindy, Floyd, Gert and Lenny – reached Category 4 strength.
Floyd first struck the Bahamas and then caused a deadly flood disaster in the eastern United States.
Lenny was an odd hurricane because it moved west-to-east in the Caribbean in November – the reverse direction of how storms usually track in that portion of the Atlantic Basin.
- ACE index: 182
- 14 named storms, 10 hurricanes, 3 major hurricanes
- 88 named storm days, 48.5 hurricane days, 9.5 major hurricane days
Forty-eight-and-a-half hurricane days occurred in the 1998 season, the fourth-most of any year in the top 10.
Hurricane Mitch was the most powerful hurricane of 1998, maxing out at Category 5 strength off the coast of Honduras. Mitch was a flood and mudslide disaster for Central America that resulted in thousands of fatalities.
Bonnie and Georges are the two other hurricanes that had significant impacts in 1998.
Georges was a tropical cyclone for 17 days that moved from the Atlantic to the Caribbean and eventually to the U.S. Gulf Coast, making seven landfalls along the way. The hurricane killed 602 people, mostly in the Dominican Republic and Haiti.
Bonnie was the third hurricane in a three-year span to directly impact North Carolina.
- ACE index: 226
- 17 named storms, 10 hurricanes, 6 major hurricanes
- 91.25 named storm days, 51.25 hurricane days, 19.25 major hurricane days
The 2017 season will long be remembered as one of the busiest and most destructive Atlantic hurricane seasons on record.
Its 51.25 hurricane days is the second most of any year in the satellite era, trailing only 1995, which had 61.5 hurricane days. 2017 also ranks second with its 19.25 major hurricane days, behind only the 2004 season's 22.25 major hurricane days.
Three Category 4 hurricanes – Harvey, Irma and Maria – made landfall in the United States following 12 years without a major hurricane (Category 3 or stronger) landfall in the country. Puerto Rico was nearly made uninhabitable by Maria, and two locations in southeastern Texas received more than 60 inches of rain from Harvey, a new tropical cyclone rainfall record in the U.S.
September 2017 was the most active month of any Atlantic hurricane season on record in terms of ACE index, which was 175. Included in the month's ACE calculation were Irma, Jose, Katia, Lee and Maria; all of those except Katia were long-lived hurricanes. Lee and Katia were the only ones to not reach Category 4 or Category 5 intensity at their peaks.
Hurricane Irma was the longest-lived Category 5 hurricane on record in the Atlantic Basin since the beginning of the satellite era in 1966, maintaining that intensity for a total of 3.25 days, according to Dr. Phil Klotzbach, a tropical scientist at Colorado State University.
2. (tie) 1995
- ACE index: 227
- 19 named storms, 11 hurricanes, 5 major hurricanes
- 121.25 named storm days, 61.5 hurricane days, 11.5 major hurricanes
1995 kicked off the so-called "active era" for the Atlantic Basin that has continued well into the 21st century. Its 61.5 hurricane days is the most of any year in the satellite era.
2. (tie) 2004
- ACE index: 227
- 15 named storms, 9 hurricanes, 6 major hurricanes
- 93 named storm days, 45.5 hurricane days, 22.25 major hurricane days
Tied with 1995 for the No. 2 spot in the top-10 is 2004 – a direct result of having the most major hurricane days (22.25) of any season in the satellite era.
Chief among those was Hurricane Ivan, which is tied with Hurricane Allen (1980) for the second-longest duration as a Category 5 – three days – in the Atlantic Basin, trailing only Hurricane Irma (2017) at 3.25 days. Ivan left a trail of destruction from the Caribbean to the southeastern United States and was a major hurricane throughout that time.
Charley and Jeanne were both major hurricanes when they struck Florida in 2004. Frances was a major hurricane for more than six days in the Atlantic before it made landfall along Florida's eastern coast as a Category 2.
- ACE index: 250
- 28 named storms, 15 hurricanes, 7 major hurricanes
- 131.5 named storm days, 49.75 hurricane days, 17.5 major hurricane days
It should come as no surprise that the hyperactive 2005 season is the most extreme in the satellite era. Twenty-eight storms accounted for 131.5 named storm days, the most in both categories for any year in the satellite era.
2005 also had the most major hurricanes in a season during the satellite era – seven. A record four hurricanes reached Category 5 status in the 2005 season, including Emily, Katrina, Rita and Wilma.
The incredible accolades of the 2005 season go on and on. See the link below for more details.
(RECAP: 2005 Hurricane Season by the Numbers)
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