A Strange and Damaging Hurricane Season Comes to an End
A strange and damaging hurricane season is officially over, and forecasters are taking stock of its many surprises. The season, which was predicted to be hyperactive, ended with 18 named storms, 11 hurricanes, and five major hurricanes, at the lower end of the range most forecasters expected.
A Season of Surprises
Philip Klotzbach, a meteorologist at Colorado State University, described the season as "one or two things that make me scratch my head." The season got off to a roaring start with Hurricane Beryl, the first Category 5 storm seen in the Atlantic Ocean in June. However, from mid-August to early September, all went quiet, a rare occurrence known as a "double-zero" event. This was the first time since 1968 that no named storms developed during this period.
The Switch Flipped and It Went Completely Off
Just when researchers thought their forecasts were turning into busts, storm activity roared back to life, with hurricanes Helen and Milton striking, causing billions in damage. Klotzbach noted that the season’s pattern was like "a switch flipped and it went completely off and completely on."
What Led to the Strange Pattern?
Researchers are studying what led to the strange pattern to boost their understanding of the factors that drive hurricanes and improve future forecasts. The reasons they predicted a busy and dangerous hurricane season were record high ocean temperatures in the Atlantic and a likelihood that La Niña, a natural pattern of variability, would take hold. However, La Niña did not develop strongly, and other factors likely combined to cause the surprising lull in activity.
Other Factors Contributed to the Lull
About 60% of hurricanes form as a result of Africa’s tropical monsoon season, which draws moisture into an area called the Sahel. This year, the monsoon developed in a different location, ending up so far north and intense that it had not had rain in 45 years. The Madden Julian oscillation, a climate pattern that travels near the equator, also likely contributed, slowing storm development in early September and then allowing hurricanes to take off later in the month.
Researching the Factors
Researchers will spend the winter investigating which factors had the most influence via climate and weather models. "It’s an opportunity to learn, to look at the system and have the Earth teach us something new," said Matthew Rosencrans, the lead hurricane forecaster at NOAA’s Climate Prediction Center.
Setting Records
Despite the mid-season break from tropical storms, 2024 set several records. Five hurricanes made landfall in the continental U.S., tying several years for the second most in history. Helene was the strongest hurricane to ever strike Florida’s Big Bend, and seven hurricanes formed in the Atlantic after September 25, the most in recorded history.
The Impact of Climate Change
Research suggests that climate change made Helene and Milton worse. Both hurricanes went through a rapid intensification process, in which a hurricane’s sustained wind speeds increase by at least 35 mph over 24 hours. The trend has become more common as global temperatures rise. Climate change is also responsible for a 20% to 30% increase in rainfall in one-day events like Milton and a 10% increase in wind speeds due to the influence of human-caused global warming.
FAQs
Q: What was the most surprising thing about this hurricane season?
A: The season’s sudden and unexpected lull in activity, followed by a surge in storms.
Q: What were the factors that contributed to the lull in activity?
A: The African monsoon’s unusual development and the Madden Julian oscillation’s impact on storm formation.
Q: How did climate change impact the season?
A: Climate change made Hurricane Helene and Milton worse, with increased rainfall and wind speeds due to rising global temperatures.
Q: Will climate change continue to impact hurricane seasons?
A: Yes, research suggests that climate change will lead to a greater proportion of named storms becoming hurricanes and more intense hurricanes.
