The worst has come to bear with Hurricane Ida. The storm has rapidly intensified into a Category 4 beast and is in the process of making landfall on Grand Isle, Louisiana.
Ida strengthened over the course of Saturday and has 150 mph (241 kph) winds as it approaches the coast. The National Hurricane Center is already receiving reports of sustained winds of 102 mph (165 kph)—the equivalent of Category 2 winds—as well as 6 feet (2 meters) of storm surge hitting Louisiana, and things will deteriorate from here throughout the day as Ida comes ashore with powerful winds, crushing surge, and torrential rain. This will be the third major hurricane to strike Louisiana in a year, following last year’s Laura and Delta.
Ida also comes as the state is in the midst of its worst covid-19 wave since the pandemic began along with a host of other background conditions that will make the recovery from Ida that much harder. In an era of what climate justice essayist calls “crisis conglomeration,” this is it.
The winds are what are rightfully grabbing everyone’s attention, but they’re far from the only danger. Ida is poised to be the fourth-strongest storm by windspeed to ever make landfall in the U.S., according to hurricane expert Philip Klotzbach. That’s small comfort, though; the storms in Ida’s company are some of the worst to ever strike the country.
The two most recent are Hurricanes Andrew and Michael, multibillion-dollar disasters that wiped coastal communities off the map in Florida in 1992 and 2018, respectively. It also ties last year’s Hurricane Laura as the strongest storm to make landfall in Louisiana. Ida’s pressure at landfall was 930 millibars, just 10 millibars higher than Katrina’s record-setting pressure at landfall. The lower the pressure, the stronger the storm. Though Ida isn’t at Katrina’s level, 930 millibars is still incredibly low pressure and a sign that the storm is capable of tremendous damage. What follows will almost certainly be a billion-dollar-plus disaster.
Not to dismiss the wind, but the greatest damage we’re likely to see from Ida will come from the water, which traditionally has been the greatest source of hurricane destruction. Specifically, it’s about how much of it Ida pushes ashore and how much the storm drops from the sky.
Storm surge could reach 16 feet (5 meters) along large parts of the coastline from the petrochemical hub of Port Fourchon (which is also poised to take a direct hit from Ida’s eyewall and the strongest winds) to the mouth of the Mississippi River. Water will come ripping through the tidal marshes and bayous that look like Swiss cheese from above, threatening the communities interspersed throughout the region.
Then there’s the rain. Ida will bring curtains of precipitation across the region, far from where its eye makes landfall. The storm will slow down as it moves inland, which means Ida’s bands of rain will repeatedly wash over the region. Up to 2 feet (0.6 meters) of rain could fall, unleashing catastrophic flooding far inland from the storm.
New Orleans sits outside the path of Ida’s eyewall, which is a small bit of only moderately terrible news. But it is on the northeast side of the storm, which is generally the side of maximum impact due to the way hurricanes rotate. That means it could still see serious impacts, as could parts of the Mississippi Gulf coast. Parts of New Orleans outside the city’s rebuilt levees could see more than 6 feet (2 meters) of surge and some pockets where waters could rise more than 9 feet (3 meters) as Ida pushes water ashore. The surge will test the levee system that was reconstructed after Katrina. It’s designed to withstand this type of surge, but this storm will be a major test.
The city is already reporting power outages, and those will likely spread across Louisiana and Mississippi as Ida moves fully onshore. Sewage overflows will become a concern as well as pumps are already starting to fail in New Orleans. That ups the odds of waterborne illnesses. Widespread curfews exist across Louisiana as the storm makes it way onshore.
Update, 8/29/21, 1:01 p.m. ET: This post has been updated with the latest forecast information as well as emerging details from the ground.