Hurricane Ida strengthened to a major hurricane early Sunday as it churned ever closer to crashing ashore along the Louisiana coast Sunday afternoon.

The Category 4 storm’s peak winds leaped to 150 mph early Sunday and could approach catastrophic Category 5 levels prior to landfall. The National Hurricane Center said the “extremely dangerous” hurricane is predicted to wallop New Orleans on the 16-year anniversary of Hurricane Katrina and threatens numerous other population centers along the northern Gulf Coast and hundreds of miles inland.

The storm’s track has shifted to the east, increasing the possibility that the storm’s core of dangerous hurricane-force winds batters New Orleans.

The powerhouse storm will push ashore an “extremely life-threatening” ocean surge of up to 12 to 16 feet above normally dry land at the coast in southeast Louisiana, the Hurricane Center warned. “Potentially catastrophic wind damage” is anticipated close to where the storm comes ashore while “life-threatening” inland flooding from up to two feet of rain is also predicted.

“Please understand this, there is the possibility that conditions could be unlivable along the coast for some time and areas around New Orleans and Baton Rouge could be without power for weeks,” the National Weather Service in New Orleans wrote Saturday night. “We have all seen the destruction and pain caused by Harvey, Michael, and Laura. Anticipate devastation on this level and if it doesn`t happen then we should all count our blessings.”

Tropical-storm-force winds are expected to reach southeast Louisiana Sunday morning, with deteriorating conditions expected thereafter into early Monday. The most dangerous conditions are probable between midmorning and early evening Sunday.

People stacked sandbags and boarded up homes Aug. 28 in the New Orleans area to get ready for Hurricane Ida, forecast to hit the Gulf Coast on Aug. 29. (Tom Moore, Jorge Ribas/The Washington Post)

New Orleans is under a hurricane warning that stretches from Louisiana’s central coast to the border with Mississippi. Storm surge warnings stretch from Louisiana’s central coast to the Alabama-Florida border, including Mobile Bay.

Forecasters’ worst fears about Ida’s potential to explosively intensify over the extremely warm waters of the Gulf of Mexico were confirmed as Ida’s peak winds catapulted 65 mph in 24 hours between 5 a.m. Saturday and 5 a.m. Sunday.

Studies have shown that warming sea surface temperatures due to human-caused climate change have increased the likelihood of rapid strengthening of tropical storm systems.

Ida’s landfall coincides with the 16th anniversary of Katrina striking Louisiana, and it could be even more intense than that historic storm. However, after Katrina, a $14.5 billion flood-protection system was constructed around New Orleans that is expected to be much more effective in keeping storm waters from inundating the city. Katrina was also an enormous storm, which allowed it to push more water ashore. Ida is more compact, although it is predicted to expand some.

“There’s been a $15 billion investment in the system over the last 16 years, and we are in a far better place than we were in 2005,” said Collin Arnold, director of the New Orleans Office of Homeland Security and Emergency Preparedness, on CNN on Saturday. “That being said, this is still a very dangerous storm.”

New Orleans Mayor LaToya Cantrell on Friday issued a mandatory evacuation order for residents outside the city’s levee system, where the surge could reach 12 feet, and called for voluntary evacuations elsewhere in the city.

Due to the storm’s predicted rapid strengthening, Cantrell said it was too late for a mandatory evacuation for areas inside the levee protection system. Instead, she instructed residents to voluntarily evacuate if they can or to shelter in place. “People need to be in their safe spaces by and no later than midnight tomorrow [12 a.m. Sunday],” she said.

Iconic images of Hurricane Katrina’s devastating destruction

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NEW ORLEANS, LA - AUGUST 30, 2005 - Water surrounds home just east of downtown in this aerial view of damage from Hurricane Katrina in New Orleans, Louisiana, Tuesday morning, August 30, 2005. (Smiley Pool/ The Dallas Morning News) MANDATORY CREDIT - ONE TIME USE ONLY IN CONJUNCTION WITH 10TH ANNIVERSARY OF HURRICANE KATRINA AND RITA (SMILEY N. POOL/The Dallas Morning News)

In addition to New Orleans, several parishes (counties) in southeast Louisiana called for mandatory and voluntary evacuations Friday ahead of the storm. A mandatory evacuation order was also issued for Hancock County in coastal Mississippi.

Last year, Louisiana was slammed by three hurricanes, including Category 4 Laura in August, and Delta and Zeta in October. The three storms caused roughly $27 billion in damage.

Ida is hitting while Louisiana sees a surge in coronavirus cases: On average, more than 4,000 new cases per day have been reported over the past week, with a 10.5 percent increase in deaths.

The Biden administration is sending a surge response team of 50 FEMA paramedics to the state and prepositioning personnel, food, water and generators ahead of the storm.

The most reliable models predict that Ida will make landfall Sunday afternoon southwest of New Orleans, nearly due south of Houma, La., although slight shifts in the track are possible. Storm impacts from wind and flooding will expand hundreds of miles beyond the storm’s center.

The core of the storm could pass directly over Houma and Baton Rouge and very close to New Orleans, Morgan City and Lafayette, with devastating wind and rain that produces widespread downed trees, power outages and flooding. Josh Eachus, chief meteorologist for Baton Rouge’s ABC affiliate, called for an “18 hour window of some of the worst weather our city has experienced in years.”

Biloxi and Gulfport, Miss., and Mobile, Ala., could also see serious impacts from coastal flooding, rain and wind, although conditions will be less severe compared to those in Louisiana.

Ida’s remnants could even prove problematic far inland, dropping a swath of heavy rainfall and isolated tornadoes across parts of the South, the Tennessee and Ohio valleys, and the Mid-Atlantic.

Ida right now

At 8 a.m. Sunday, Ida had 150 mph peak winds as it headed to the northwest at 15 mph, centered 100 miles southeast of Houma, La.

The storm had undergone “rapid strengthening” overnight, the Hurricane Center wrote, its peak winds increasing 35 mph in 6 hours. Some additional strengthening is possible, the Hurricane Center said.

The storm had tapped into a powder keg, transiting ocean waters with temperatures in the upper 80s and an atmosphere replete with moisture. “These conditions, combined with the improved structure of the hurricane, should allow Ida to rapidly intensify until it makes landfall,” the Hurricane Center wrote.

Surge forecast

Ida’s winds will push water up along the coast, likely resulting in a devastating storm surge that will occur over a broader area and have a bigger footprint than the winds. The Hurricane Center warned that the surge could reach heights of 12 to 16 feet between Port Fourchon, La., and the mouth of the Mississippi River.

A eight- to 12-foot surge is possible southeast of New Orleans, with five to eight feet of inundation likely on Lake Pontchartrain. Coastal Mississippi, including Biloxi and Gulfport, could see a similar storm tide, with a few feet of surge possible all the way east in Mobile Bay.

While much of New Orleans is protected from surge by the Hurricane Storm Damage Risk Reduction System — a system of levees, pumps and flood gates — outside this system, the Weather Service warns that the surge could bring “[w]idespread deep inundation,” “structural damage to buildings, many washing away,” “roads washed out or severely flooded,” “extreme beach erosion,” and “massive damage to marinas.”

“Much of coastal LA is just marsh so this surge will penetrate well inland and unless you are within the Hurricane Risk Reduction System you are putting your life in danger and do not expect to receive any help if you are caught and cut off,” the Weather Service wrote.

Surge heights can vary significantly over small distances due to the nuances of coastal topography, landfall location and tidal effects. The worst surge ordinarily occurs east of the storm’s center, where southerly winds directly intersect the coastline.

Wind forecast

Where Ida makes landfall in central or southeast coastal Louisiana, winds gusting above 140 mph are possible. That will be the case only at the immediate shoreline where the eyewall, or inner ring of extremely strong winds surrounding the eye, crashes ashore.

Wind gusts of 80 to 110 mph could penetrate 100 miles inland and reach Baton Rouge. Because of the slight shift east in Ida’s forecast track Saturday, the likelihood of hurricane-force winds in New Orleans has increased. The Weather Service now says gusts over 100 mph are possible in the city. “If there is any more of a jog east these winds will be even higher,” the Weather Service wrote. “Winds funneling through some of the high rises will be even stronger.”

The Weather Service will likely opt to issue extreme wind warnings where the eye tracks ashore, which could affect Houma and Morgan City. That’s a special alert reserved for winds topping 115 mph in major hurricane eyewalls that can cause tornado-like wind damage.

Where the eyewall intercepts the coast, the Weather Service warns of “[s]tructural damage to sturdy buildings, some with complete roof and wall failure,” and “[m]any roads impassable from large debris.”

Winds will decrease with distance outside of the eyewall, but they are still likely to cause widespread tree and roof damage as well as power outages across much of Louisiana, some of which could last weeks.

In addition to its damaging straight-line winds, Ida is also expected to spawn tornadoes, especially east of its center. “Tornadoes will be possible Sunday into Monday across the northern Gulf Coast states including parts of eastern Louisiana, Mississippi, central and southern Alabama, and the Florida Panhandle,” the Hurricane Center wrote.

Rain forecast

The potential exists for serious flooding due to Ida’s heavy rain, as well. The Weather Service forecast 10 to 18 inches of rain in southeast Louisiana and southern Mississippi, with up to two feet in a few spots. The result will be “life-threatening flash and urban flooding and significant river flooding impacts,” the Hurricane Center wrote.

Rainfall amounts will drop off significantly on the west side of the storm, with a steep gradient through western Louisiana. For example, Shreveport, at Louisiana’s Texas border, may wind up with barely half an inch.

New Orleans is likely to see 10 to 15 inches of rain, and it’s not out of the question that a few communities could see more than that. This amount of rain will test the city’s network of 99 pumps, 96 of which are currently functional. If rainfall amounts top 15 inches in the city, “it will overwhelm the pumps with extremely dangerous flash flooding possible,” the Weather Service wrote.

It added: “At the same time winds could be dangerous and this would prevent people from trying to find higher ground.”

Beyond southeast Louisiana, flash flood watches are up for much of the Deep South ahead of Ida, with widespread four- to eight-inch or five- to 10-inch totals and locally higher amounts expected for coastal Alabama, the western Florida Panhandle, and central Mississippi through Monday night.

Ida could then trek northeast through the Tennessee and Ohio valleys, unloading three to six inches Tuesday and Wednesday. Heavy rain could also reach parts of the interior Mid-Atlantic and Northeast midweek.

Caroline Anders contributed to this report.