Does global warming change that?

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The powerful tornado that claimed one person’s life and caused extensive damage as it swept through the New Orleans area on Tuesday was one of the strongest in the region’s history and one of the most 100 tornadoes to hit in the past four decades.

Preliminary results from the National Weather Service investigation revealed an 11-mile trail of destruction and concluded the tornado was likely an EF-3 on the 0-5 scale used to categorize tornadoes. Damage was seen in Jefferson, Orleans and St. Bernard parishes, including Arabi, where 25-year-old Connor Lambert was killed.

Such powerful storms are relatively rare across the country and in Louisiana, said Harold Brooks, senior researcher at the National Severe Storms Laboratory in Norman, Oklahoma. But they happen more often than many of those unaffected realize, he said.

Statewide, 59 tornadoes of magnitude EF-3 or greater have been reported in Louisiana since 1980, according to weather service records.

Four of these occurred in the New Orleans metropolitan area, including an EF-4 tornado in St. John the Baptist Parish in December 1983.

With the country firmly in the grip of warming temperatures fueling more extreme storms and more intense wildfire seasons, Brooks and other researchers often wonder if climate change is affecting tornadoes.

So far, scientists don’t have definitive answers, Brooks said.

In Louisiana’s case, the state is in a region “fairly vulnerable” to extreme weather, although it may not experience as many tornadoes as states like Mississippi and Alabama.

Seven hurricanes and tropical storms made landfall in Louisiana in 2020 and 2021, and thousands are still trying to recover. At least one resident of a home badly damaged by Tuesday’s tornado in Arabi was displaced by Hurricane Ida last year. The state has recorded 50 disaster declarations since 2000.

Residents of the state “have become all too familiar with rebuilding after tragedy and loss,” Gov. John Bel Edwards said Wednesday.

A second tornado in St. Tammany Parish on Tuesday was rated EF-1, with winds of 90 mph. The tornadoes blew out windows, ripped roofs off, toppled trees and injured several people.

In general, parts of the South, including Tennessee and Alabama, have seen an increase in tornado activity in recent years. The country has also seen an increase in the number of tornadoes that occur in one-day outbreaks, and traditional spring and summer tornado seasons start earlier in the year and end later, Brooks and D. ‘others.

While it’s tempting to link these observations to global warming, Brooks said scientists haven’t made any clear connections.

They suspect global warming could increase the potential energy available to form the types of convective storms that give rise to tornadoes, said Tyler Fricker, an assistant professor at the University of Louisiana Monroe.

A recent report by the United Nations Intergovernmental Panel on Climate Change found high confidence in increased rainfall rates associated with severe convective storms in a warming world. Already, the warming Gulf of Mexico is pumping more moisture into warmer air and sending more intense, flooding rains across much of the eastern half of the country.

However, the UN panel said “significant uncertainty” remained about the predicted effects on tornadoes.

Researchers are eager to answer these questions, Fricker said. While they don’t see a change in the number of EF-4 and EF-5 tornadoes, they do see evidence to suggest that tornadoes may stay on the ground longer or expend more energy than in the past.

Warmer temperatures and more humidity in the air may influence some of the activity changes at some level, Fricker said, “but we don’t know what that level is.”

He has spent the past year studying tornado activity in Louisiana, with a focus on fatalities and casualties.

Parishes to the west are seeing more activity than the New Orleans area, partly from storms coming in from Texas and partly from tropical activity off the Gulf of Mexico, he said. declared.

Lafayette is the city most often hit by tornadoes, followed by Shreveport, which has nearly twice as many EF-3 tornadoes as other parishes and the most tornado-related deaths and injuries, he said. . The risks in Lafayette and Shreveport are “significantly higher” than in New Orleans and Baton Rouge.

Still, the four parishes affected Tuesday in the New Orleans area have seen more than 130 tornadoes since 1980. This includes an EF-3 tornado with winds of 150 mph in Orleans Parish on February 7, 2017. An EF -3 associated with Hurricane Andrew’s landfall in Louisiana in 1992 hit nearby St. John the Baptist Parish.

EXPLAINER: Why the south gets more killer tornadoes at night

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Powerful tornadoes are relatively rare in the New Orleans area: is global warming changing that? (2022, March 24)
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Teresa H. Sadler