The 2020 Atlantic hurricane season officially ends today, wrapping up a truly exhausting season that smashed records and dealt repeated blows to vulnerable coastal communities.
“It’s just been crazy,” says Allison Wing an assistant professor of meteorology at Florida State University. “For the forecasters and scientists involved I think everyone is really just a bit tired at this point and kind of ready for it to be over.”
This was the most active Atlantic hurricane season ever documented. Thirteen storms strengthened into hurricanes, the second highest number in recorded history. Thirty storms grew strong enough to earn a name, beating 2005’s record of 28 storms. The World Meteorological Organization actually ran out of storm names by September, turning to the Greek alphabet for labels for the first time since 2005. For comparison, an average season only has a dozen named storms.
Researchers knew this year would be a doozy from the beginning. “All of the things pointed in the direction of having a very active season, and then it came to fruition,” says Matthew Rosencrans, a meteorologist at NOAA’s Climate Prediction Center.
Sea surface temperatures in the Atlantic were warmer than usual, fueling stronger storms. The West African monsoon, a major wind system that can influence storms over the Atlantic, was also stronger this year. There was also weaker vertical wind shear over the Atlantic, which is good news for hurricanes since stronger wind shear can tear the storms apart. The season became even busier when a La Nina climate pattern developed in September and weakened the wind shear even more.
While a busy season was predictable, nine storms this season threw additional curveballs at forecasters when they rapidly intensified as they approached land. “To me, that’s one of the most notable things about 2020 is just all these storms rapidly intensifying up to or almost up to the point of landfall,” says Phil Klotzbach, a research scientist in the Department of Atmospheric Science at Colorado State University.
Storms that gain power so quickly can be especially dangerous because it gives people less time to prepare for the fierce winds and rising waters. There are only two other years — 1995 and 2010 — with nine rapidly intensifying storms on the books, according to Klotzbach. Unfortunately, rapid intensification appears to be happening more often as global average temperatures continue to rise.
The fury of these intense storms was not evenly distributed. Some places got hit repeatedly, with barely any room between storms to brace themselves. Eta and Iota devastated Nicaragua and Honduras within two weeks of each other this November. Iota, the strongest hurricane on record to strike Nicaragua, triggered catastrophic flooding and landslides; at least 40 people have died across Central America and Columbia as a result. Louisiana was hard hit, too. Five storms, nearly half of all of the storms that made landfall in the US this year, struck the state. The most devastating was Hurricane Laura, which made landfall with category 4 strength and killed at least 23 people in the state. Iota and Laura pushed tens of thousands more from their homes.
This year’s Atlantic hurricane season was horrible, but by some measures, it still pales in comparison to 2005. While 2020 had more storms, 2005 had stronger storms. Thankfully, no single storm this year matched the pain wrought by 2005’s Hurricane Katrina which killed well over 1,000 people.
Now, the season is formally over, but 2020 isn’t one to stick with formalities. Officially, the season begins on June 1st each year and ends on November 30th. But this year, the first named storm, Arthur, developed in May. That made this the sixth consecutive year that a storm earned its name before June 1st. Normally, the Atlantic’s season follows a curve, with the busiest part of the season in September before gradually tapering off. This year, some of the strongest hurricanes — Eta and Iota — struck unusually late, and they may not be the last storms to form. Just like it disregarded the official start to the season, 2020 may persist past its official end. There’s no guarantee that we won’t see more stragglers through December.
Forecasters are still at work and are currently keeping an eye on a low-pressure system in the eastern Atlantic, which could become Kappa.