Record-breaking 2021 Atlantic hurricane season ends

The 2021 Atlantic hurricane season officially ended Tuesday, going down in history as the first time that two consecutive seasons have exhausted the list of 21 English storm names.

The big picture: Above-average sea surface temperatures led to fierce storms that left their mark on the Gulf Coast as well as mid-Atlantic, when Category 4 Hurricane Ida swept ashore in coastal Louisiana on Aug. 29 and went on to kill more than two dozen people in the mid-Atlantic.

By the numbers: This hurricane season was the third-most active season on record in terms of named storms, according to the National Oceanic and Atmospheric Administration (NOAA).

• It was the sixth straight above-average Atlantic hurricane season, and occurred during a longer time period of above-average storm activity in the Atlantic, dating back to 1995.
• Studies have shown that a combination of natural climate variability and human-caused global warming may be behind that trend.
• Climate change likely contributed to a greater proportion of high-end storms of Category 3, 4 and 5 intensity and increased tendency of storms to rapidly intensify.

In a frightening display of rapid intensification, Hurricane Ida's maximum sustained winds increased by 65 mph in a 24-hour period prior to landfall.

• The storm's central air pressure plummeted by 52 millibars over the same time period. The lower the pressure is, the stronger the storm.
• A total of five Atlantic storms underwent rapid intensification this year, including Ida, NOAA found.

Hurricane Ida came ashore near the oil and gas industry facilities in Port Fourchon, Louisiana, making the state the first to ever see back-to-back years with hurricanes that made landfall with sustained winds of 150 mph or greater, according to meteorologist Steve Bowen, head of catastrophe insight at Aon.

In a cruel twist, Ida's death toll was largest far from its landfall location, when it interacted with a preexisting weather front and dumped historic amounts of rain in a short time across the Mid-Atlantic. More than 40 people perished in the floods.

• New York's Central Park received 3.15 inches of rain in one hour during the height of the storm.

• In New York City, residents drowned in basement apartments, public transport came to a standstill, and city officials were forced to reckon with how they were so unprepared despite ample warnings of a likely deluge.

What's new: NOAA and NASA scientists gained new insights into Atlantic hurricanes by observing them from space, aircraft, the sea surface and underwater.

• Researchers at NOAA’s Atlantic Oceanographic and Meteorological Laboratory deployed five new extreme weather Saildrones to improve their understanding of what processes take place where the ocean meets the atmosphere.
• One uncrewed Saildrone captured the first-ever video and measurements at the surface of the ocean during a major hurricane, withstanding 125-mph winds and 50-foot waves during Hurricane Sam.
• Data from Saildrones, NOAA and Air Force Reserve aircraft and other platforms helped improve the accuracy of computer models used to predict hurricane movement and intensity.

What's next: The 2022 Atlantic season begins on June 1.