New Orleans Without Power as Hurricane Ida Batters Louisiana

Video

NEW ORLEANS — Hurricane Ida battered Louisiana on Sunday with an onslaught of harsh winds and floodwaters, leaving nearly a million people without power including much of New Orleans and at least one person dead.

The hurricane made landfall as a powerful Category 4 storm, which weakened to a Category 2 storm on Sunday night with maximum winds of 105 miles per hour. It sent hundreds of thousands of people scrambling to evacuate, and left countless others bracing for survival, in an eerie echo of Hurricane Katrina, which made landfall in Louisiana 16 years ago to the day.

Ida’s eye came ashore late Sunday morning near Port Fourchon, La., with maximum sustained winds of 150 miles an hour, just shy of the 157 m.p.h. winds of a Category 5 storm. Hurricane-force winds extended up to 50 miles from the storm’s center, which was moving northwestward in the afternoon across a region of bayous, lakes and wetlands, menacing Baton Rouge and New Orleans.

The storm’s trajectory and strength present a high-stakes dual threat to the region. Storm waters are expected to strain the levees and pumps and other hurricane defenses that were reinforced around New Orleans after Hurricane Katrina. At the same time, hospital systems are already under strain as Louisiana grapples with one of the worst coronavirus outbreaks in the nation.

With the storm passing close to New Orleans through the night, it was impossible to determine the full extent of destruction and potential loss of life on Sunday. But scenes and reports from across the region were not promising.

“There is no doubt that the coming days and weeks are going to be extremely difficult for our state and many, many people are going to be tested in ways that we can only imagine,” Gov. John Bel Edwards said at a news conference Sunday afternoon.

Mr. Edwards warned that conditions were extremely hazardous — and worsening — and that a long night may be ahead. “Nobody should be expecting that, tonight, a first responder is going to be able to answer a call for help,” he said.

In Prairieville, La., about 30 miles southeast of Baton Rouge, a. 60-year-old man died after a tree fell on a home, according to the Ascension Parish Sheriff’s Office.

Nearly one million people were without power across Louisiana as of Sunday night, according to reports from utility companies compiled by PowerOutage.us.

In a statement on Sunday night, Entergy, a power company with 2.9 million customers across the South, said that all eight transmission lines that power the New Orleans area were out of service, adding that it was unclear when power might be restored.

Entergy texted residents on Sunday night to report that all of New Orleans was without power. “Due to catastrophic transmission damage, all of Orleans Parish is currently without power,” the text said. “More information will be shared when available.” Entergy New Orleans said on Twitter that the outage was caused by a load imbalance between its transmission and generation.

As the storm made landfall, there were reports of high winds and roofs being ripped off homes in Grand Isle, La., a coastal town on a barrier island on the Gulf of Mexico near where the storm’s center came ashore, according to Kevin Gilmore, a meteorologist with the National Weather Service.

“Hopefully there is really nobody there — that’s all I can hope for,” Mr. Gilmore said.

The storm spawned tornado warnings in parts of western Louisiana and areas in southern Mississippi and Alabama.

Weather officials have warned that Ida could bring storm surge waters across a wide swath of the region, from Port Fourchon northeastward to Ocean Springs, Miss. In some places, waters could reach as high as 16 feet above high tide.

More than 980,000 people in New Orleans and nearby cities were under a flash flood warning that lasted through Sunday night.

St. Bernard Parish officials confirmed that the hurricane caused 22 barges near Chalmette, east of New Orleans, to break loose and float down stream on the Mississippi River.

John Lane, the parish’s executive director of coastal operations, said officials did not believe the levees in the area were at risk, but there was concern about effects on essential infrastructure such as water intake and nearby refineries.

On the streets of New Orleans, the wind whipped in fearsome gusts as strong as 70 miles an hour. There were few cars in motion, except for the occasional howling emergency vehicle. Downtown, a few homeless people tucked themselves into the porticos of buildings. But the people who remained in New Orleans had mostly hidden themselves away.

“This is the time to stay inside,” Mayor LaToya Cantrell said. “Do not venture out. No sightseeing.”

On Sunday afternoon, the storm, moving northward, stalled west of New Orleans, causing 3 to 4 inches of rain to fall per hour and compounding the risk of flooding, said Benjamin Scott of the National Weather Service.

The storm arrived just as Louisiana was grappling with another crisis. In recent days, there have been more than 2,500 people hospitalized with Covid-19 across the state, nearing the previous record. Mr. Edwards said on Sunday that the situation had complicated disaster planning.

“Evacuating these large hospitals is not an option, because there are not any other hospitals with the capacity to take them,” he said.

Ida also intensified very quickly, leaving little time to evacuate.

The storm was propelled in speed and strength by the Gulf’s very warm waters, which provide energy to storms. Warming waters have been affected by climate change.

For many, the storm stirred painful reminders of the death and devastation that Katrina wrought in 2005, leaving psychological scars that still run deep in the city. Katrina killed 1,833 people, inflicted more than $100 billion in damage, and submerged large stretches of New Orleans, leading to scenes of suffering that horrified the nation.

“It’s definitely triggering to even have to think about this,” said Victor Pizarro, a health advocate and a resident of New Orleans who planned to ride out the storm with his husband in the Gentilly Terrace neighborhood. “It’s exhausting to be a New Orleanian and a Louisianian at this point.”

Video

transcript

Back

transcript

Louisiana Braces for Hurricane Ida

Louisiana residents rushed to evacuate or hunkered down with supplies ahead of Hurricane Ida. The Category 4 storm is one of the most powerful systems to hit the region since Hurricane Katrina, bringing life-threatening storm surge and winds.

We’ve decided to take off. Yeah, because just like with Hurricane Katrina, we’re not trying to be here for the disaster, so we are taking no chances. We’re leaving. Boarding up. We boarded up the two buildings across, I’ve been two days now boarding up a lot of buildings, a lot of buildings, getting ready, crossing our fingers. I went to Academy, and I bought a dozen life jackets just in case, you know. I hope I get to bring them back. I hope I don’t have to use them, but I’d rather have it and not need it than not have it and need it.

Eduardo Medina and Jesus Jiménez contributed reporting

The heavy rains and tidal surge from Hurricane Ida prompted a flash flood emergency Sunday night in areas south of New Orleans, as a failed levee in the town of Jean Lafitte left up to 200 people in “imminent danger,” the National Weather Service said.

Mayor Tim Kerner Jr. said rescue boats were mobilizing but would not be able to deploy until daybreak. “If you’re in an attic, you’re on a roof, rest assured you’re going to be all right,” he said on WDSU television. “Once you see that wind starting to die down, look on the horizon, because we’re coming.”

The Weather Service issued the flash flood warning just before midnight Eastern time for the town of Jean Lafitte, about 22 miles south of New Orleans, and surrounding areas.

“This is a life threatening situation,” the Weather Service said on Twitter. “Seek higher ground now.”

More than 3,000 people were under the flash flood emergency, which was in effect until 7:45 a.m. Eastern time on Monday.

The Weather Service in New Orleans said it had received reports from local officials that a levee had failed around Jean Lafitte and nearby Lafitte, adding that more than 200 people were in “imminent danger.” It was not clear if the levee was being overtopped or had been breached.

Earlier in the night, the Weather Service also said it had received several reports of significant flooding in Laplace, La, about 30 miles northwest of New Orleans, adding that the eastern wall of the hurricane was hitting the area at the time.

“Take whatever means are necessary to protect your life,” the Weather Service said.

Across Twitter, several people were asking for help on Sunday night, sharing their address and asking to be rescued themselves or seeking help for others in need of rescue.

In an interview with WDSU, Ricky Templet, a council member in Jefferson Parish, said that a new levee in town had been designed for a tidal surge of up to seven feet.

“Apparently the surge has exceeded that,” he said. “The water is rapidly rising with these winds still coming out of the South. The water is still pushing up into the bayou areas and rising rapidly.”

Mr. Templet said a lot of new homes in town had been raised, from 11 feet to some as high as 15 feet. “I’m not sure if any of those homes that have been raised are being threatened. Their yards and the surrounding area would be.”

The area has been under mandatory evacuation.

Hurricane Ida’s fierce winds whipped through New Orleans Sunday afternoon, and heavy rains battered streets and buildings across the city.

In the Algiers Point neighborhood, directly across the Mississippi River from the French Quarter, windows shook and tree limbs were sent flailing. Steely gray skies were barely visible through the stretch of oak trees lining Opelousas Avenue. Some neighborhood streets were already strewn with leaves and broken branches.

Many residents evacuated the city before the storm made landfall, but some stayed behind, determined to ride out the storm in their own homes or those of friends or relatives.

Most houses were not boarded up, but residents appeared to have taken to heart officials’ advice to pull trash cans inside, leaving the streets uncommonly empty.

The winds began to rise in the morning as the storm drew near the coast to the south. Neighbors could be seen taking their dogs for a quick walk around the block or running after trash cans blowing down the street. Residents stepped out onto stoops to take in houseplants and wind chimes, which could become projectiles when the winds reach their peak strength, expected around early evening.

Prolonged power outages are expected to have the biggest impact for those who stayed in the city, with food and medicine spoiling in inoperable refrigerators and hot weather making daily life uncomfortable for everyone and causing heat stroke in some. Power trouble had already begun on Sunday, as the lights flickered and went out in Algiers, then the 7th Ward, then the 9th Ward.

The Sewerage and Water Board sent a notice just before noon that a number of its stations throughout the city were losing power, which could cause sewers to back up in homes if residents did not reduce the amount of wastewater they send into the system through showers, dishwashing and toilets flushing.

“These stations will be out of service until the storm passes,” the notice read.

In other parts of the region, the storm’s effects were yet to arrive in force.

Ida’s outer bands drizzled over a sleepy Sunday morning in Lafayette, La. Morning Masses were still scheduled in the predominantly Catholic city of just over 120,000 people. South of town, gas station workers wrapped plastic around their pumps, which had mainly been out of unleaded fuel since midmorning on Saturday.

At a public park cut out of cane fields in Youngsville, south of Lafayette, Robert and Lauren Felder continued a nine-year tradition of playing tennis before the hurricane hit. Their two children climbed over a jungle gym while, near the court, families bagged up sand from a tall mound.

Though their neighbors had boarded up their homes, the Felders limited their storm preparation to picking up loose items in the yard, seeing little cause to shield their windows.

“Plywood is more expensive than windows right now,” Mrs. Felder said.

Those who evacuated on Saturday did so in heavy traffic. Lessie LeBlanc-Melancon and her family left their mobile home in rural Ossun, taking six hours to make a normally 3 ½-hour trek. At a hotel in Conroe, Texas, they found families from New Orleans, including one that had stuck it out through Katrina 16 years ago and couldn’t stand to go through that again.

Flood gates near Morgan City in St. Mary Parish were closed ahead of the storm. Just a handful of St. Mary Parish residents fled north to shelters. Once projected to be in the maw of the storm as it sprinted across the Gulf, the coastal parish is now expecting moderate gusts and manageable bulges in the tide, according to the parish emergency coordinator, Tim Broussard. “The worst will be over by midnight,” Mr. Broussard said.

In New Orleans, where memories of Hurricane Katrina are never far away, and even less so on the storm’s 16th anniversary, some residents said they were having a hard time putting much faith in local officials’ assurances that the city’s levees would hold this time and that the local pumps would churn water out of the city before floodwaters rose.

“I feel like the levees should hold, but again, if they didn’t, I wouldn’t be surprised, because we all thought they would hold during Katrina, but they didn’t,” said Chris Dier, a local schoolteacher. “If I were to find out they broke, I wouldn’t be surprised at all.”

Mr. Dier evacuated his home in Arabi, next to the Lower Ninth Ward, on Saturday.

He said his home was gutted by Hurricane Katrina in 2005, and “I just have a really eerie feeling about this one.”

By the time Hurricane Ida made landfall in Louisiana as a Category 4 storm, more than 400,000 utility customers in Louisiana were without power, and by Sunday night, that number had risen to nearly one million, including much of the city of New Orleans.

In a statement on Sunday night, Entergy, a power company with 2.9 million customers across the South, said that all eight transmission lines that power the New Orleans area were out of service, and that it was not clear when power might be restored.

More than 199,000 customers in Jefferson Parish, part of the greater New Orleans region, were without electricity, according to PowerOutage.us, which tracks utility performance across the country. More than 193,000 customers were without power in Orleans County, while about 11,000 were without power in Plaquemines Parish, south of the city.

Before the outage in New Orleans, Entergy said that, based on historical restoration times, people in the direct path of the storm could be without power for as long as three weeks.

“While 90 percent of customers will be restored sooner, customers in the hardest-hit area should plan for the possibility of experiencing extended power outages,” the company said in a statement.

Both companies said that they would have crews working to restore service after the storm passes.

The authorities in the regions with the most customers without power said that the loss of electricity was happening swiftly. Within a 10-minute period on Sunday afternoon, outages in Jefferson Parish increased to 54,000 from 46,000, Cynthia Lee Sheng, the parish president, said at a news conference.

Gov. John Bel Edwards of Louisiana said at a news conference on Sunday that restoring power was a priority, in part because so many were in hospitals being treated for Covid-19.

“I understand that generators are great,” he said, “but over time they tend to fail, and so getting the power restored quickly but having prioritized restoration so that your most critical needs are restored first is going to be really, really important.”

Hurricane Ida, which struck the Louisiana coast on Sunday with winds of 150 miles an hour, gained power faster more than most storms. Because of climate change, such rapid strengthening is happening more often as hurricanes pick up more energy from ocean water that is warmer than before.

But in a summer of extreme weather, Ida’s intensification was extreme.

According to the National Hurricane Center’s forecast bulletins, the storm’s maximum sustained winds as of Saturday morning were about 85 m.p.h., making it a Category 1 hurricane. Less than 24 hours later they were 65 m.p.h. stronger, bringing Ida close to a Category 5.

The storm intensified more than the hurricane center’s forecast, which had called for maximum winds reaching 140 m.p.h. The hurricane center’s definition of rapid intensification is at least a 35 m.p.h. increase in wind speed in 24 hours. Ida strengthened that much in just six hours overnight.

Climate change is part of the reason. Researchers have found that the frequency of rapidly intensifying Atlantic hurricanes has increased over the past four decades as ocean temperatures have risen, in large part because warmer water provides more of the energy that fuels these storms. In the 1980s, there was about a 1 percent chance that a hurricane would undergo rapid intensification. Now, there’s a 5 percent chance.

But experts who study the behavior of hurricanes said other factors played a role with Ida, including seasonal warming of the Gulf of Mexico, the amount of moisture in the atmosphere and the presence or absence of winds that can affect the structure of a storm.

Right now the Gulf is extremely warm because it accumulated heat throughout the summer. It’s this seasonal warming, which happens in the Atlantic Ocean as well, that makes mid-August through October the most active part of the hurricane season every year.

But it’s not just the surface temperature of the Gulf that’s important, said Joshua Wadler, a researcher with the University of Miami and the National Oceanic and Atmospheric Administration. Hurricanes actually cool the ocean as they travel across it, because they stir up the water down to about 150 feet, mixing in colder water from below.

In this case, Ida traveled across water that was much warmer down to that depth. Probes sent into the water by hurricane hunter aircraft on Saturday revealed that the temperature, after it had been mixed by Ida, was about 30 degrees Celsius, or 86 degrees Fahrenheit, Dr. Wadler said.

“That’s on the very high end of sea surface temperatures that hurricanes ever experience,” he said.

The storm’s path happened to track over this warm water, what scientists call an eddy, said Chris Slocum, a NOAA researcher.

“Ida found the perfect path across the gulf, where the warmest water is,” he said, and that provided plenty of energy for the storm to extract. “You could say it’s a worst-case scenario.”

Dr. Slocum compared the situation to that of Katrina, in 2005, which crossed a cooler water column as it neared Louisiana, weakening from a Category 5 to a Category 3. Ida did not encounter any cooler water.

“This one is continuing the upward trend,” he said. “The only thing that’s going to stop the intensification process is landfall,” he said.

Eddies occur in the Gulf every year, formed when part of a looping current breaks off, Dr. Wadler said. And while it’s extremely difficult to link a specific one to climate change, this one “is as deep as we’ve seen in a very long time,” he said.

While ocean temperatures are most important, two other factors affect how much and how quickly a storm strengthens, Dr. Slocum said.

Atmospheric moisture affects the thunderstorms that make up a tropical cyclone. The more humid the air, the more these storms will survive and persist. And the way these thunderstorms interact with each other, particularly at the eye of the storm, can affect whether it strengthens or weakens.

Wind shear — changes in wind speed and direction with height in the atmosphere — can also affect the structure of a hurricane. If the wind shear is too strong, “you can tear a storm apart,” Dr. Slocum said.

The hurricane center’s forecasters had been watching wind shear closely. It had been a factor as the storm entered the Gulf on Friday, giving Ida an asymmetric structure. But the shear dissipated on Saturday, allowing the storm to assume a more regular spiral shape.

The effect on wind speed can be likened to what happens with figure skaters during a spin. Skaters who keep their arms in a tight, precise position will rotate faster. But if one of their arms is extended, they’ll rotate much more slowly.

Forecasting whether a hurricane will intensify rapidly can be difficult, Dr. Slocum said.

“It’s kind of a Goldilocks problem,” he said. “If one of these ingredients is a little bit off, we’re not going to see it.”

As Hurricane Ida moves farther inland in the coming days, it is expected to lose strength, but continue to pose a danger to many parts of the Southeast, the National Hurricane Center said.

On Monday, Ida will likely bring heavy rainfall, and possibly severe flooding, to Louisiana, the southern parts of Mississippi and coastal communities in Alabama. The rainfall totals could reach as much as 24 inches in some parts of southeast Louisiana.

Coastal Alabama and the western parts of Florida could see five to 10 inches of rain through Tuesday morning, and in central Mississippi, up to a foot of rain, starting on Sunday.

Tornadoes are also possible on Monday in southeast Louisiana, Southern Mississippi, southwest Alabama and the western Florida Panhandle.

The storm is expected to turn northeast on Monday, tracking across the Middle Tennessee Valley, including Humphreys County, where 20 people were killed this month as flash floods tore through communities there. The area could see up to six inches of rain on Tuesday and Wednesday, the Hurricane Center said.

The National Weather Service in Nashville issued a flood watch for most of Middle Tennessee starting on Monday night.

By Wednesday, the storm will move through the Upper Ohio Valley, dropping as much as six inches of rain.

The rainfall totals for all of these areas could result in flash flooding, the Hurricane Center said.

As Hurricane Ida barreled through Louisiana on Sunday, it dumped enough rain to exceed at least one levee southeast of New Orleans.

Around 5:30 p.m. Eastern time, the Plaquemines Parish said on Facebook that it had received reports of a levee that had “overtopped” in the Braithwaite area, southeast of New Orleans, and urged those in the sparsely populated area to evacuate.

“SEEK HIGHER GROUND IMMEDIATELY,” the parish said.

A 10-foot high surge topped the levee, although it has not yet been breached, said Ricky Boyett, spokesman for the Army Corps of Engineers in New Orleans.

After the parish’s announcement, the Weather Service issued a flash flood emergency for the Braithwaite area, urging residents to seek higher ground.

“It is a very serious situation,” said Hannah Linsey, a meteorologist with the National Weather Service in New Orleans. “It takes a lot for a levee to be overtopped. It’s not something that happens very often at all.”

The flash flood emergency, which was in effect through 11 p.m., was issued for an area with a population of about 80 people. It wasn’t immediately clear how many people in the area had evacuated ahead of the storm.

“We had ordered a mandatory evacuation on Friday, so that’s why we think it was pretty desolate,” said Kirk Lepine, the Plaquemines Parish president, on Sunday evening.

The community is outside the federal storm risk reduction system that is providing protection to the greater New Orleans area, said Christina Stephens, a spokeswoman from the governor’s office in a statement. The National Hurricane Center had cautioned that overtopping of local levees was possible in areas outside of the risk reduction system.

The levee near Braithwaite is not one of the levees built by the Army Corps of Engineers; it is maintained by the Plaquemines Parish, according to Mr. Boyett. The corps is currently constructing new levees in the parish that can reach as high as 30 feet depending on elevation.

The overtopping “wasn’t a surprise,” Mr. Boyett added. “That’s an area that is subjected to some pretty high surges.”

Chelsea Brasted contributed reporting.

Video

transcript

Back

transcript

Louisiana’s Covid Surge Complicates Its Response to Hurricane Ida

As the Category 4 storm slammed the state, Gov. John Bel Edwards said that evacuating hospitals was not an option because of the high number of coronavirus patients.

We’re going to see a very, very powerful storm that will travel across southeast Louisiana and will exit into Mississippi, probably still at hurricane strength. And this is not the kind of storm that we normally get. This is going to be much stronger than we usually see. And quite frankly, if you had to draw up the worst possible path for a hurricane in Louisiana, it would be something very, very close to what we’re seeing. We’re in a very dangerous place with our hospitals, as you know. Yesterday’s count, we still have 2,450 in our hospitals with Covid, on top of all of the other individuals who are in a hospital. And quite frankly, evacuating our Tier 1 hospitals is not going to be an option. There aren’t hospitals with the capacity to take them. And so making sure that they can maintain power and water, have access to all of the food that they need and oxygen and other things, that’s going to really consume a lot of our time and attention because we know that the lights could be out, power could be out for weeks. I know the storm is focused on southeast Louisiana, but we’re going to be sheltering people across the state in big numbers and for quite a time, it appears. And the challenge there, are the challenges you always have, but additionally, Covid. Because you don’t really want to keep people in a congregate shelter any longer than absolutely necessary.

Louisiana hospitals scrambled Sunday to deal with two severe challenges, the landfall of Hurricane Ida and a surge of Covid that has stretched hospital capacity and left daily deaths at their highest levels in the pandemic.

Louisiana’s medical director, Dr. Joseph Kanter, had asked residents on Friday to avoid unnecessary emergency room visits to preserve the state’s hospital capacity, which has been vastly diminished by its most severe Covid surge of the pandemic.

And while plans exist to transfer patients away from coastal areas to inland hospitals ahead of a hurricane, this time “evacuations are just not possible,” Gov. John Bel Edwards said at a news conference.

“The hospitals don’t have room,” he said. “We don’t have any place to bring those patients — not in state, not out of state.”

The governor said officials had asked hospitals to check generators and stockpile more water, oxygen and personal protective supplies than usual for a storm. The implications of a strike from a Category 4 hurricane while hospitals were full were “beyond what our normal plans are,” he added.

Mr. Edwards said he had told President Biden and Deanne Criswell, the administrator of the Federal Emergency Management Agency, to expect Covid-related emergency requests, including oxygen.

The state’s recent wave of Covid hospitalizations has exceeded its previous three peaks, and staffing shortages have necessitated support from federal and military medical teams. On Friday, 2,684 Covid patients were hospitalized in the state. This week Louisiana reported its highest ever single-day death toll from Covid — 139 people.

Oschner Health, one of the largest local medical systems, informed the state that it had limited capacity to accept storm-related transfers, especially from nursing homes, the group’s chief executive, Warner L. Thomas, said. Many of Oschner’s hospitals, which were caring for 836 Covid patients on Friday, had invested in backup power and water systems to reduce the need to evacuate, he said.

The pandemic also complicated efforts to discharge more patients than usual before the storm hits. For many Covid patients who require oxygen, “going home isn’t really an option,” said Stephanie Manson, chief operating officer of Our Lady of the Lake Regional Medical Center in Baton Rouge, which had 190 Covid inpatients on Friday, 79 of them in intensive care units.

The governor said he feared that the movement of tens or hundreds of thousands of evacuees in the state could cause it to lose gains made in recent days as the number of new coronavirus cases began to drop. Dr. Kanter urged residents who were on the move to wear masks and observe social distancing.

Hurricane Ida’s arrival set off dangerous storm surge along the Gulf Coast and raised worries of severe flooding. The National Hurricane Center warned of “catastrophic storm surge, extreme winds and flash flooding.”

The flooding on Sunday afternoon was concentrated on the coasts of Louisiana and Mississippi. The outer bands of the storm had earlier brought heavy rain and strong winds to Florida and Alabama. Because the rapid intensification of the storm led many to stay home, many now face flooding risks that they might have avoided if they had more time to evacuate, said Mayor LaToya Cantrell of New Orleans.

“We still have the potential for upward of eight to 12 feet of surge and then 12 to 16 feet in some areas,” said Julie Lesko, a senior service hydrologist with the New Orleans-Baton Rouge office of the National Weather Service. “Right now, we are seeing tidal gauges already starting to climb,” meaning that the sea level was rising, she said.

The Federal Emergency Management Agency said it was beginning to prepare for what it called “catastrophic flooding.”

One area of concern was Grand Isle, La., on a barrier island on the Gulf of Mexico, where officials said about 40 of the 800 residents stayed behind to ride out the storm after a mandatory evacuation order was issued on Friday. All of the power was out and the one road into the community was flooded.

“Those folks are just going to have to hunker down and wait for the storm to pass before it’s safe and before we can get to them,” Cynthia Lee Sheng, the Jefferson Parish president, said at a news conference on Sunday.

“Our concern from the beginning,” she added, “has been this level of storm surge for that island and the people who chose to remain on it.”

Videos on social media and from meteorologists showed the shore of Gulfport, Miss., being flooded. Water had reached Highway 90, and parts of it had grown dangerous, officials said. A curfew was in effect there, according to the Harrison County Sheriff’s Office, and the area was under a flash flood warning.

Shell Beach, La., had reached a storm surge of nearly seven feet above normal. The water levels in many other locations along the coast had started to climb, according to the National Weather Service.

The New Orleans Sewage and Water Board had already asked residents to conserve water after some sewer lift stations lost power. It raised the possibility that sewer lines could back up into homes.

Hurricane Ida’s landfall Sunday brought dangerous wind, storm surge and rain to the Gulf Coast exactly 16 years after the arrival of Hurricane Katrina, one of the most costly natural disasters in American history, which left more than 1,800 dead and did more than $100 billion in damage.

The overall impact of storm surge from Ida is predicted to be somewhat less severe than that from Katrina. The 2005 storm was blowing at Category 5 strength in the Gulf of Mexico before weakening as it approached landfall, so it generated enormous storm surge, reaching more than 20 feet in parts of the Mississippi coast. Current projections put the potential storm surge of Ida at 12 to 16 feet in the worst areas.

“Fifteen-foot sure can do a lot of damage,” said Barry Keim, a professor at Louisiana State University and Louisiana State Climatologist. “But it’s going to be nothing in comparison with Katrina’s surge.”

Improvements to the levee system following Katrina have made the New Orleans metro area better prepared for storm surge. But the areas that are likely to receive the most severe surge from Ida may be less equipped to handle it than the area that was hit by Katrina, said Dr. Keim.

Ida made landfall to the west of where Katrina struck, bringing the most severe storm surge to the Louisiana coast west of the Mississippi River rather than east of the river, as Katrina did.

“We are testing a different part of the flood protection in and around southeast Louisiana than we did in Katrina,” Dr. Keim said. “Some of the weak links in this area maybe haven’t been quite as exposed.”

While the impacts of Ida’s storm surge are expected to be less severe than Katrina’s, Ida’s winds and rain are predicted to exceed those that pummeled the Gulf Coast in 2005. Ida made landfall as a Category 4 storm with sustained winds around 150 miles an hour; Katrina came ashore as a Category 3 with winds of 125 m.p.h.

“It could be quite devastating — especially some of those high-rise buildings are just not rated to sustain that wind load,” said Jamie Rhome, acting deputy director of the National Hurricane Center.

The severe damage from Hurricane Laura, which struck southwest Louisiana last year as a Category 4 storm, was caused primarily by high winds. The storm caused 42 deaths and damage costing more than $19 billion.

Ida’s rainfall also threatens to exceed Katrina’s highs.

The National Hurricane Center estimates that Ida will drench the Gulf Coast with 8 to 16 inches of rain and perhaps as much as 20 inches in some places. Katrina brought 5 to 10 inches of rain, with more than 12 inches in some areas.

“That is a lot of rainfall,” Mr. Rhome said of the forecast for Ida. “Absolutely the flash flood potential in this case is high, very high.” Combined with storm surge, he said, that much rain could have a “huge and devastating impact to those local communities.”

After Hurricane Katrina put New Orleans underwater, the United States built one of the largest flood-protection systems in the world, at a cost of $14.5 billion. Now Hurricane Ida will show how well it works.

The system includes 192 miles of levees and flood walls in New Orleans and neighboring parishes, according to the Flood Protection Authority, the body that operates it.

That system also includes a 1.8-mile-long surge barrier that stretches across Lake Borgne at the eastern edge of the city, 244 land-based flood gates and additional navigable flood gates that remain open for boat traffic and close when a storm approaches.

The city is also protected by pumps that the flood authority says are “so powerful that they could fill the Superdome with water every 90 minutes.”

Despite the massive nature and cost of that system, its goal is not to prevent flooding entirely; in the words of the flood authority, it “significantly reduces the risk of flooding.” And it is designed for a so-called 100-year storm — a storm with a 1 percent chance of happening in any given year.

The storm surge from Hurricane Ida could exceed that threshold.

After Katrina, lawmakers initially had bolder ambitions to protect New Orleans from the next superstorm, as John Schwartz and Mark Schleifstein reported in The New York Times in 2018. Congress called for “interim protection” against 100-year storms, followed by a system that would protect against a storm even more powerful than Katrina.

That would require building something far larger and more expensive, some experts concluded: Rather than building with a 100-year storm in mind, the system would have to be engineered for a 5,000-year storm.

But that option turned out to be too expensive to pursue. “The interim level became the benchmark,” Mr. Schwartz and Mr. Schleifstein wrote.

Hurricane Ida will be the first real test of that system, according to Daniel Kaniewski, who was in charge of resilience at the Federal Emergency Management Agency until 2020.

But Mr. Kaniewski, who watched Hurricane Katrina from the White House in 2005 as an aide to President George W. Bush, said that what worried him most wasn’t the flood protection system, given the enormous investments that had been made.

Rather, he said, he was concerned about the other types of infrastructure that are needed to keep people safe in New Orleans from Hurricane Ida.

“The communications infrastructure and energy infrastructure and health care infrastructure are absolutely essential to protect the citizens, every bit as much as the physical flood infrastructure,” said Mr. Kaniewski, now a managing director at the insurance brokerage company Marsh McLennan.

Whether or not those additional systems are strong enough to keep operating in the face of a hurricane like Ida, he said, “remains to be seen.”

Hurricane Ida is the first major storm to strike the Gulf Coast during the 2021 season, hitting a region in many ways still grappling with the physical and emotional toll of a punishing run of hurricanes last year.

The Atlantic hurricane season of 2020 was the busiest on record, with 30 named storms, 13 of which reached hurricane strength. There were so many storms that forecasters ran through the alphabet and had to take the rare step of calling storms by Greek letters.

Louisiana was dealt the harshest blow, barraged repeatedly by storms, including Hurricane Laura, which was one of the most powerful to hit the state, trailed six weeks later by Delta, which was weaker than Laura but followed a nearly identical path, inflicting considerable pain on communities still gripped by the devastation from the earlier storm.

The state is struggling to claw its way back. Gov. John Bel Edwards of Louisiana said the state had $3 billion in unmet recovery needs. In Lake Charles, which was ravaged by direct hits from both hurricanes followed by a deadly winter storm and flooding in May, local officials recently renewed a plea for federal aid as the city has failed to regain its footing; much of it has yet to recover and many residents, unable to find adequate or affordable housing, have fled.

The impact of Ida underscores the persistient peril facing coastal communities as a changing climate helps intensify the destructive force of the storms that have always been a seasonal part of life in the region.

President Biden cited the growing danger in May when he announced a significant increase in funding to build and bolster infrastructure in communities most likely to face the wrath of extreme weather.

As they braced for the arrival of Hurricane Ida, oil and gas companies shut down more than 95 percent of their production in the Gulf of Mexico, making this storm the first of the year to significantly disrupt those industries.

Workers were evacuated from nearly half of the area’s staffed production platforms and from all 11 rigs in the Gulf, federal officials said on Saturday. BP, Chevron, Phillips and Shell were among the companies that closed facilities. Oil prices were likely to rise when trading resumed on Sunday night, analysts predicted.

The disruption could have an effect on gasoline prices ahead of Labor Day, traditionally one of the year’s high-demand peaks.

“It’s a little speculative to say yet what’s going to happen, but it’s going to be an event,” said Tom Kloza, the global head of energy analysis at Oil Price Information Service. “This could lead to a mini-price spike.”

On Sunday, Colonial Pipeline, which carries refined gasoline and jet fuel from Texas up the East Coast to New York, said it was temporarily halting fuel deliveries from Houston to Greensboro, N.C., Reuters reported. The company, which pre-emptively shut down its pipeline in May after a ransomware attack, said in a note to shippers that fuel would be available at its terminals throughout the Southeast, and that it would resume full service when it is safe to do so.