Closing the books on the 2024 hurricane season, one of the costliest on record

Today marks the end of the 2024 hurricane season. And in a season of firsts, the 2024 hurricane season had plenty. Seasonally, the 2024 Atlantic hurricane season is the first season to feature multiple Category 5 hurricanes since 2019 and one of the costliest in history.

18 named storms formed across the Atlantic basin, with 11 becoming hurricanes, 5 of them strengthening into major hurricanes. 8 hurricanes made landfall; 5 of which struck the United States.

This year’s numbers were above the averages of 14 named storms, 7 hurricanes and 3 major storms that form during a typical season, but below the well advertised record season that was predicted.

The season officially began until Tropical Storm Alberto. Alberto formed on June 19, marking the slowest start to a hurricane season in a decade.

Even with a beleaguered start, 2024 was the ninth successive season with above average activity. An average season produces 14 named storms, seven hurricanes and three major hurricanes.

Hurricane Beryl was the earliest Atlantic basin Category-5 hurricane on record. Beryl caused significant storm surge flooding across parts of Texas and Louisiana after making landfall near Matagorda, Texas, as a Category-1 storm.

Photo via Juan Lozano

Hurricane Debby Debby made landfall as a Category 1 hurricane slamming into the Big Bend region of Florida on Aug. 5, with 80 mph winds. About 350,000 people lost power in Florida due to the storm. Hurricane Debby's primary impact across Florida was flooding due to heavy rainfall, but a notable storm surge of 3 to 5 feet across portions of the Nature Coast and the southeast Big Bend still brought damage to the immediate coastline where many are still recovering from Hurricane Idalia which came ashore less than one year prior.

Debby drenched Florida, Georgia, North Carolina and South Carolina. Greenpond, South Carolina, reported 14 inches of rainfall, surpassing monthly averages for August in just one day.

The system moved slowly up the U.S., bringing tornadoes and flooding to Ohio, Pennsylvania, Virginia, New York, New Hampshire and Vermont before moving into Canada.

Category 2 Hurricane Francine overperformed on final approach to south-central Louisiana on September 11th. Francine made landfall as a Category 2 hurricane in Terrebonne Parish, Louisiana, on Sept. 11. The storm brought heavy winds and torrential rains and caused severe flooding in several areas. Significant damage was reported in the coastal areas and further inland, like New Orleans. Many communities hit by Hurricane Francine were still recovering from Hurricane Ida in 2021.

Hurricane Helene made landfall as a Category-4 storm on Florida’s Gulf Coast on September 26. Helene was the first-ever Category 4 hurricane to make landfall in Apalachee Bay, obliterating coastal towns in Dixie and Taylor Counties with 15 feet or more of storm surge and winds likely exceeding 120 mph. Helene draped a tidal wave of sand across many parts of western central Florida causing billions in damage before it moved up the southeastern United States which caused catastrophic flooding across the southern Appalachians.

There was widespread wind damage from the Gulf Coast to the North Carolina mountains and storm surge flooding along portions of western Florida. Helene was labeled the “Hurricane Katrina” of the Appalachians. Preliminary data indicate that Helene was the deadliest hurricane to affect the continental United States since Katrina in 2005, with more than 150 direct fatalities, the majority of which occurred in North Carolina and South Carolina.

An atmospheric river of moisture slammed into the southern Appalachians, and wrung out a deluge of 15-30” of rainfall, causing the worst flooding in eastern Tennessee and western North Carolina since at least 1916.

Hurricane Helene marked the first time ever that NOAA’s National Hurricane Center (NHC) forecasted a system to become a major hurricane before it became a tropical depression or tropical storm. The National Weather Service forecasted potentially catastrophic rainfall totals and rain rates over western North Carolina more than 48 hours ahead of Helene’s impact.

Hurricane Milton made landfall as a Category-3 near Siesta Key, Florida, on October 9 and resulted in a tornado outbreak that produced 46 tornadoes and caused torrential rainfall and localized flooding with total rainfall amounts in excess of 10-15 inches. Milton produced a destructive storm surge between Siesta Key, Florida, and Ft. Myers Beach, Florida, including Charlotte Harbor. Milton's explosive rate of rapid intensification was among the highest ever recorded, with a 90-mile-per-hour increase in wind speed during a 24-hour period from October 6 to October 7. Hurricane Milton rocketed into the second Category 5 hurricane of the season; it was also the strongest tropical cyclone worldwide in 2024.

Hurricane Milton impacted some of the same areas in Florida that were still recovering from Helene. Milton became the strongest hurricane of the 2020s so far in the Atlantic Basin, the strongest hurricane of the year in the world, and the most intense hurricane in the Atlantic basin since Wilma (2005). Milton also became the 5th most intense hurricane by atmospheric pressure, and the 6th costliest storm in U.S. history.

The National Hurricane Center forecasted Hurricane Milton’s potential major hurricane landfall along the coast of west-central Florida nearly two days before it formed into one, and more than four days before landfall.

As a one-two punch on the continental U.S, Helene and Milton rank second only to Harvey and Irma as the most destructive duo of hurricanes in a single year. And Florida was struck by 3 tropical systems this season. If one more would have impacted the state, it would have been an all time record of landfalling storms in Florida. Milton made history in another way when it reached hurricane strength, marking the first time in recorded history that the Atlantic basin has hosted three active hurricanes simultaneously in the month of October. Milton formed alongside Kirk and Leslie, two hurricanes that developed west of Africa and continued swirling at sea without doing much damage to nearby lands.

Photo via CSU/CIRA & NOAA

Following Milton, the storm’s destruction combined with Helene, Beryl, Debby and Francine added to a whopping $191 billion in damages for the 2024 season, making one of the costliest hurricane seasons on record in the Atlantic, behind 2017’s $224 billion.

Many forecast agencies including NOAA, called for 17-24 named storms to develop, with an average baseline of 22 storms. As the weeks went by into September, there were questions of whether the 2024 season would live up to the predictions. Some of these questions were addressed in Colorado State University’s early September report. While the tropical cyclone experts explained the peak season lull in activity, there was still confidence that above average activity would occur by the end of the season.

Activity dramatically increased in late September with several strong storms developing. Gordon, Isaac, Joyce, and Category 4 Kirk belatedly brought the season back to life and back to reality in the open waters of the eastern Atlantic in the second half of the month.

Other notable highlights of the 2024 hurricane season: Oscar had the smallest hurricane force-wind field on record in the Atlantic Basin (5-6 miles wide). Rafael was the strongest November hurricane in nearly 40 years. 5 landfalling hurricanes and 1 unnamed system accounted for numerous U.S. areas impacted. The 2024 season featured the most U.S. landfalling tropical systems since 2020. This year was only 1 of 5 seasons to have multiple Category 5 hurricanes since 2000.

All told, the 2024 season began with a roar, followed by a well advertised but unpredicted lull…only to finish like a lion. While the 2024 Atlantic Season finished with the climatological average in total counts of named storms, its intensity was anything but average. Well above average SSTs (sea surface temperatures) and ENSO-neutral conditions led to the development of several significant Atlantic hurricanes. Among these, Hurricane Beryl set a record as the earliest Category 4 and 5 hurricane in June and July. Hurricane Helene brought a deadly storm surge and catastrophic inland flooding. And Hurricane Milton’s rapid intensification resulted in a pressure below 900 mb, becoming the most intense hurricane since Wilma in 2005.

The 2024 Atlantic hurricane season will undoubtedly be remembered for its volatility and devastation, as well as the abnormal global atmospheric and oceanic conditions that drove it.