Should hurricane season be longer? These experts say yes. Here's why - NOLA.com

Should hurricane season be longer? These experts say yes | Environment | nola.com

There was more bad news for storm-weary Louisiana residents this week: A team of scientists said hurricane season should be even longer.

The research team of climate scientists say the season, which spans six months from June 1 to November 30, is not long enough anymore.

One of the scientists is state climatologist and LSU professor Barry Keim. Keim says that they began looking into the issue in 2020 -- the most active hurricane season on record -- because they noticed that named tropical storms were more frequently occurring outside of the Atlantic Hurricane Season.

Moving back the start of the season would help local officials and residents prepare, he said. Keim mentioned the possibility of starting the season about two weeks earlier, but said that would be up to the National Hurricane Center and World Meteorological Organization to decide.

"That was such a busy season," Keim said of 2020. "We put together a research paper on that specific year, and that paper just kept growing. Then we started investigating when the hurricane seasons were actually getting longer in duration. It makes you ask the question, do we actually have the boundaries correct on when hurricane season begins?"

The research team includes experts from LSU, the University of New Hampshire, Colorado State University and the Southern Climate Impact Planning Program. SCIPP is a collaborative research effort between LSU, the University of Oklahoma, Texas A&M University and Adaptation International, an organization that helps communities and businesses become more climate resilient.

For the past three years, these researchers have studied records on when named storms have happened outside of hurricane season, whether that's earlier or later than the official hurricane season. Keim says that this is the first effort of its kind.

They discovered that, in eight of the last nine years, there's been at least one named storm before hurricane season started. In two of these years, 2016 and 2020, there were two preseason storms.

Keim said their hypothesis is that warmer ocean temperatures throughout a longer portion of the year -- a result of climate change -- plays the largest part in extending hurricane season. For tropical cyclones to form, the ocean has to be at least 80 degrees fahrenheit.

Keim acknowledged another possible factor though: that many more storms are being detected because of how advanced modern hurricane forecasting technology has become. In the past, forecasters only used data collected from airplanes and boats to determine if a tropical storm had formed.

"With these short-lived storms in particular, in the early 1900s, we would have no way to even detect those," Keim said. "The fact that we can detect those now with satellites -- is that what's causing us to find more storms earlier and later in the seasons? That's the dilemma we're trying to figure out."

There have been other efforts to look into extending hurricane season. The World Meteorological Organization, which decides when hurricane seasons officially start and end, said it has reviewed the possibility of starting the season on May 15 instead of June 1. In 2021, it put together a team of researchers to study if there have been many storms outside of hurricane season, but based on their findings decided not to extend it.

In 2022, NHC Senior Hurricane Specialist and Metairie native Eric Blake along with other hurricane specialists published findings showing that starting hurricane season half a month earlier would only include an additional 1% of storms.

From 1921-1970, 99% of named storms happened within the normal hurricane season. However, from 1971-2020, 96% of tropical storms happened within the season. Many of the storms outside the season are either short-lived or subtropical, and rarely become hurricanes.

However, Keim said that his team considered short-lived storms, such as a subtropical storm from January of this year, and other outliers, and removed them from their final considerations.

"We've eliminated all of the short storms that lasted for two days or less," Keim said. "And we're still finding the trends."

The research paper from Keim's team is close to being finished, and will be submitted for peer review in the coming weeks.