2021 Hurricane Season Wrap

 

Hurricane Sam, September 2021 (Source: NASA)

The 2021 Atlantic hurricane season concludes next week on November 30.  This has been the Atlantic’s sixth consecutive busier than average season and will finish with 21 tropical storms, of which 7 became hurricanes, including 4 major hurricanes.  A “major” hurricane is a Category 3/+ on the Saffir-Simpson Hurricane Wind Scale with sustained winds of at least 111 mph. 

An “average” Atlantic hurricane season has 14 tropical storms, 7 hurricanes with 3 major hurricanes according to NOAA.  That’s the 30-year average based on 1991-2020 data.  The previous 30-year average for 1981-2010 was replaced earlier this year, and that was for 12 tropical storms, 6 hurricanes with 3 major ones.  The uptick in averages can be attributed to the high frequency of above average Atlantic hurricane seasons in recent years.

The 2021 Atlantic hurricane season got underway before its official June 1 start when “Ana” was named a storm on May 22.  It was a weak system that developed over the central Atlantic with little impact.  However, Ana was significant for getting this hurricane season off to a fast start.  Three more tropical storms developed in June and the first hurricane of the season, Elsa, developed in early July.

The first major Atlantic hurricane of 2021, Grace, reached peak intensity as a Category 3 storm on August 21.  Next, Category 4 Hurricane Ida made landfall in Louisiana on August 29, 2021.  Ida tied the record for strongest landfalling hurricane in Louisiana state history based on sustained winds (150 mph).  The remnants of Hurricane Ida brought heavy rain, gusty winds and severe weather to the Mid-Atlantic Region. 

Less than a month later, Hurricane Sam became the strongest Atlantic hurricane of 2021.  It reached peak intensity as a Category 4 storm over the central Atlantic with sustained winds of 155 mph.  Although the minimum central air pressure was identical (929 millibars or “mb) in hurricanes Ida and Sam; Sam was declared the strongest hurricane of the Atlantic season since its sustained winds were a little higher.

Despite seeing an above average number of tropical storms and hurricanes – no Category 5 hurricanes developed for a second consecutive season.  That follows a four-year stretch in which the Atlantic had at least one Category 5 hurricane through 2019.  While November 2020 saw two powerful, Category 4 Atlantic hurricanes, this November has been quiet by comparison with its lone named storm, Tropical Storm Wanda, having dissipated on November 7.