There was a collective sigh of relief Tuesday as the Atlantic hurricane season officially came to an end.
Although tropical systems can occur outside the official season, which runs from June 1 to Nov. 30, the likelihood of any new storms is very low as the Northern Hemisphere moves into winter.
This year was the sixth straight with an above-average hurricane season, making for a record stretch of hyperactive tropical activity. The final count of named tropical cyclones came to 21, compared to an average of 14; there were seven hurricanes, which is average; and there were four major hurricanes, compared to an average of three.
With 21 named storms, 2021 was just the third season in history to exhaust the regular list of names. The two others were 2005 and 2020.
The most legendary hurricane of the season will be Hurricane Ida, one of the most accurately forecast hurricanes in recent history. Several days out, forecast models were in consensus about a high likelihood that a rapidly intensifying major hurricane would strike the Louisiana coastline.
Ida made landfall Aug. 29 near Port Fourchon as a 150-mph Category 4 hurricane, tying 2020's Laura and the Last Island hurricane of 1856 as the strongest to ever strike the state.
It occurred on the 16th anniversary of the Hurricane Katrina.
The highest wind gust was 172 mph, recorded near Port Fourchon. New Orleans experienced wind gusts up to 90 mph, which knocked out power to the entire city. More than 1 million customers lost power in Louisiana alone.
After Ida slammed Louisiana, its remnants moved up into the Northeast, spawning destructive and deadly flooding across parts of Pennsylvania, New Jersey and New York.
New York City picked up 3.15 inches of rain in one hour. That broke the record for the wettest hour ever in the city and turned roads into rivers and subway stations into waterfalls. Dozens of people died, most of them trapped in basement apartments or inside vehicles.
Ida came after Tropical Storm Henri, which made landfall the previous week, on Aug. 22, and caused record rainfall for the area.
Given the death toll and the destruction left by Ida, the name is likely to be retired by the National Hurricane Center and the World Meteorological Organization, which make the official decision.
If it is retired, Ida would join the long list of other "I" names to have been retired. Meteorologists often say, "Beware the letter I," because it has the most retired names.
Other notable storms were Larry and Sam, for their intensity and longevity. Both remained major hurricanes for several days. Sam was the strongest of the season, peaking at 155 mph, just 2 mph shy of Category 5.
Fortunately, Sam stayed over the open Atlantic and was no threat to land.
The fingerprints of climate change were evident in several of this year's tropical cyclones. Six of the seven hurricanes went through rapid intensification, defined as an increase of 35 mph or more in 24 hours. Ida had the most impressively rapid intensification, strengthening by 65 mph in 24 hours.
The destructive flooding from heavy rain was also linked to climate change. A warmer atmosphere can hold more water, which means record rain is expected to become more frequent and more intense in the future.
The 2021 season is estimated to be the fourth-costliest Atlantic hurricane season, with economic losses expected to exceed $70 billion, said Brian McNoldy, a senior research associate at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science.
Ida and Hurricane Nicholas and tropical storms Elsa and Fred were all billion-dollar disasters. Ida is tied with Sandy in 2012 as the fourth-costliest hurricane in U.S. history.