December 3, 2021

Hurricanes Katrina vs Ida: Difference between similar storms as New Orleans braces for impact

Hurricane Ida is trying eerily like a harmful sequel to 2005’s Hurricane Katrina, the most expensive storm in American historical past. However there’s just a few still-to-come twists that might make Ida nastier in some methods, however not fairly as horrific in others.

Ida is forecast to make landfall on the identical calendar date, August 29, as Katrina did 16 years in the past, placing the identical normal a part of Louisiana with about the identical wind pace, after quickly strengthening by going over a similar patch of deep heat water that supercharges hurricanes.

What may very well be completely different is essential although: Course and measurement.

Katrina hit Louisiana from due south, whereas Ida is coming to the identical a part of the state from southeast. A day-and-a-half earlier than landfall Ida’s hurricane-force winds prolonged 13 miles (21 kilometers) from the middle in comparison with 106 miles (170 kilometers) for the far more huge Katrina on the similar time earlier than landfall.

“This has the potential to be more of a natural disaster whereas the big issue in Katrina was more of a man-made one” due to levee failures, mentioned College of Miami hurricane researcher Brian McNoldy. Levee failures pushed Katrina’s loss of life toll to 1,833 and its general harm to about $176 billion in present {dollars} and consultants do not anticipate Ida to come back close to these totals.

DIFFERENT DIRECTION

Ida is coming to the identical normal place from a barely completely different path. A number of hurricane consultants worry that distinction in angle could put New Orleans extra within the harmful storm quadrant – the suitable entrance a part of a hurricane – than it was in Katrina, when town was extra devastated by levee failure than storm surge. Katrina’s northeast quadrant pushed 28-foot (8.5-meter) storm surges in Mississippi not New Orleans.

Ida’s “angle is potentially even worse,” McNoldy mentioned. As a result of it’s smaller “it’s not going to as easily create a huge storm surge … but the angle that this is coming in, I think is more conducive to pushing water into the lake (Pontchartrain).”

Pictures: Hurricane Katrina made landfall close to New Orleans Aug. 29, 2005

That northwestern path of Ida not solely places New Orleans extra within the bullseye than it did in Katrina, nevertheless it additionally extra targets Baton Rouge and essential industrial areas, mentioned meteorologist Jeff Masters, who flew hurricane missions for the federal government and based Climate Underground. He mentioned Ida is forecast to maneuver by means of “the just absolute worst place for a hurricane.”

“It is forecast to track over the industrial corridor between Baton Rouge and New Orleans, which is one of the key infrastructure regions of the U.S., critical to the economy, there’s hundreds of major industry sites there I mean petrochemical sites, three of the 15 largest ports in America, a nuclear power plant,” Masters mentioned. “You’re probably going to shut down the Mississippi River for barge traffic for multiple weeks. “

“It’s not just the coastal impact. It’s not just New Orleans,” mentioned meteorologist Steve Bowen, head of world disaster perception on the danger and consulting agency Aon. “We’re certainly looking at potential losses well into the billions.”

SIZE MATTERS

The distinction is measurement isn’t just bodily enormous, nevertheless it issues for damages. Storms which can be larger in width have bigger storm surge due to the broader push of the water.

Ida “is not going to generate the huge storm surge like Katrina did, it’ll have more focused storm surge like (1969’s) Camille,” Masters mentioned.

However bigger in measurement storms are sometimes weaker, Bowen mentioned. There is a commerce off of intense harm in a smaller space versus much less harm, however nonetheless unhealthy, in a wider space. Bowen and Princeton College’s Gabriel Vecchi mentioned they do not know which situation can be worse on this case.

RAPID INTENSIFICATION

Ida is about to hit an eddy of what is referred to as the Loop Present. The Loop Present is that this deep patch of extremely heat water. It takes heat water off the Yucatan Peninsula does a loop within the Gulf of Mexico and spins up the jap fringe of Florida into the Gulf Stream. Water above 79 levels (26 levels Celsius) is hurricane gas.

Usually when a storm intensifies or stalls it takes up the entire area’s heat water after which hits colder water that begins to weaken the storm or not less than retains it from additional strengthening. However these heat water spots preserve fueling a storm. Katrina powered up this fashion and Ida is forecast to do the identical. The eddy that Ida goes to go over has
needed heat water going greater than 500 ft (150 meters) deep, “just a hot tub,” McNoldy mentioned. Meaning a lot of fast intensification.

“Running over these Loop Current (eddys) is a very big deal. It’s really dangerous,” mentioned local weather and hurricane scientist Kossin of The Local weather Service. “It could be explosive.”

Prior to now 40 years extra hurricanes are quickly intensifying extra usually and local weather change appears to be not less than partly to be blame, Kossin and Vecchi mentioned. Hurricane Grace already quickly intensified this yr and final yr Hanna, Laura, Sally, Teddy, Gamma and Delta all quickly intensified.

“It has a human fingerprint on it,” mentioned Kossin, who with Vecchi was a part of a 2019 research on current fast intensifications.

NEW EYEWALL

After a hurricane quickly intensifies it turns into so robust and its eye so small that it usually cannot fairly preserve going that method, so it types an outer eyewall and the within eyewall collapses, Kossin mentioned. That is referred to as eyewall substitute.

When a brand new eyewall types, usually a storm turns into bigger in measurement however a bit weaker, Kossin mentioned. So key for Ida is when and if that occurs. It occurred for Katrina, which steadily weakened within the 12 hours earlier than it made landfall.

Nonetheless, lots of the different forces like crosswinds that made Katrina weaken on the final minute aren’t there for Ida, McNoldy mentioned.