Last September meteorologists witnessed a rare event: Five named tropical systems spinning in the Atlantic basin — at the same time.
Hurricane Paulette, Tropical Storm Sally, Tropical Storm Teddy, Tropical Storm Vicky and Tropical Depression Rene were seen together on a single satellite image. It was the second time in hurricane season history that five or more systems were churning in Atlantic waters at the same time. Technically speaking it was four named storms with Rene becoming remnants, but it was still a rare sight to see.
Reflective of the limited breathing room storms were experiencing in the basin, the Miami office of the National Hurricane Center was also getting cramped with more staff observing more storms, said Ken Graham, director of the NHC. COVID-19 restrictions already presented a challenge on spacing for staff who would wait in the parking lot for shift changes to happen as a means of avoiding unnecessary contact. Still, five separate system required plenty of bodies in the office.
“We were basically at capacity with the number of consoles and people,” Graham said.
With that in mind; the phenomenon inspires the question, just how many storms can the Atlantic Ocean hold in its basin at one time?
The short answer is: we’re not sure, said Philip Klotzbach, a hurricane specialist at Colorado State University.
“It would probably be extremely unlikely to get more than five named storms at once in the Atlantic. I always figure we can take the most storms that we’ve ever observed and add one,” Klotzbach said.
The reason being, hurricanes don’t play nicely with each other, and often deter the growth of other storms, if they get too close.
“If storms get too close to each other, they tend to either merge, or one will shear the other one apart,” Klotzbach said.
That actually did happen during the 2020 hurricane season when Hurricane Teddy helped tear apart both Vicky and Wilfred with an enormously powerful amount of upper-level circulation, records show.
On top of that, the conditions for a hurricane to form need to be just right, let alone for multiple hurricanes. The recipe for a hurricane is a combination of warm waters, sufficiently low vertical wind shear, enough moisture, instability and enough disturbances to take advantage of those conditions, said Michael Brennan, branch chief of the hurricane specialist unit at the National Hurricane Center.
When meteorologists saw multiple storms form last year it was eye-opening given at how unlikely it was to happen at all, Brennan said.
“This level of activity is unusual because even during the peak months of the hurricane season (August through October), it’s rare to have conditions favorable for storms to form and maintain themselves over a large enough area to get five systems at once,” he said.
However unlikely it is, meteorologists have seen it happen before. The first time was in 1971. It was also September when there were five simultaneous named storms — there were actually six storms but one of them was unnamed, which formed off the west coast of Africa. In a three-day period, meteorologists observed six active cyclones of tropical depression strength or greater — Edith, Fern, Ginger, Heidi Irene and the unnamed storm. Luckily, most of these storms didn’t cause much destruction. The exception was Edith, which briefly made landfall over Nicaragua and Honduras as a Category 5 major hurricane. It quickly degenerated and re-entered the Gulf of Mexico.
Atlantic storm records show there also were a couple of times where as many as four hurricanes were spinning at the same time. The first time was long before the current modern naming convention, back on Aug. 22, 1893. The second time occurred from Sept. 25-26 in 1998 with hurricanes Georges, Ivan, Jeanne and Karl.
Research on a “hurricane limit” in the Atlantic Basin is lacking, but it is something meteorologists keep an open mind for especially as the 2021 season is about to begin on June 1. CSU, the National Oceanic and Atmospheric Administration and AccuWeather have all predicted that the upcoming season has a high probability of being as hyperactive as the 2020 season, which produced the most named storms in Atlantic Hurricane Season history.