Category 4 Ida builds up as it roars towards Louisiana

NEW ORLEANS • Hurricane Ida gained power rapidly as it crossed the Gulf of Mexico on its way to smashing into Louisiana, threatening to unleash mass flooding and destruction in New Orleans.

The Category 4 hurricane has top winds of 241kmh, the National Hurricane Centre said yesterday. Only two other storms on record have made landfall in Louisiana with winds that powerful.

"I feel sick to my stomach watching," said Mr Eric Blake, a forecaster at the National Hurricane Centre, on Twitter. "This is a very sobering morning."

Ida is barrelling into New Orleans on the 16th anniversary of Hurricane Katrina, one of the most devastating natural disasters in US history. When it hits, the storm will be the biggest test yet of the region's levees and infrastructure that were rebuilt after Katrina.

Ida, poised to come ashore just south-west of New Orleans, is expected to drive ocean levels up by as much as 4.9m and dump 610mm of rain. Winds will be strong enough to rip roofs from houses, and snap trees and power poles. Blackouts could last weeks.

Forecasters expect the storm to grow even stronger as it approaches. It is currently set to bring the most powerful winds to Louisiana, based on records going back to 1851, and its central pressure rivals Katrina, according to Dr Phil Klotzbach, a hurricane researcher at Colorado State University.

If Ida's winds gain just a little more power, it could become a Category 5 storm, said Dr Todd Crawford, director of meteorology at commercial forecaster Atmospheric G2. Only four Category 5 storms have hit the contiguous United States.

In addition to Ida, the hurricane centre is tracking four more potential storms in the Atlantic as well as Hurricane Nora, which is raking Mexico's Pacific coast.

New Orleans has asked residents to evacuate or take shelter. The levee gates are closed in many areas, hospital wards have been cleared out, oil refineries and offshore production have shut down, and thousands of people have fled.

The storm could damage close to one million homes along the coast, according to CoreLogic. It is forecast to run directly over chemical plants, refineries and the Louisiana Offshore Oil Port. All told, damage and losses could exceed US$40 billion (S$53.8 billion), said Dr Chuck Watson, a disaster modeller at Enki Research.

"It could be catastrophic," said Mr Jim Rouiller, lead meteorologist at the Energy Weather Group.

As at yesterday, 537 flights had been cancelled in New Orleans, Dallas and Houston till today, according to airline tracking service FlightAware. Louis Armstrong New Orleans International Airport was thronged with locals lining up for outbound flights or trying to rent vehicles to flee the city. Queues at rental car kiosks were hours long.

President Joe Biden has declared a state of emergency for Louisiana.

New Orleans is below sea level and depends on levees and pumps to keep the ocean and river out. The Mississippi River in downtown New Orleans has already risen about 61cm since last Saturday and is forecast to rise 1.2m higher, said the National Weather Service.

Even if the levee system holds and keeps the surge at bay, New Orleans could face a major flood risk from the rain alone, said Dr Ryan Truchelut, president of Weather Tiger. The Federal Emergency Management Agency has deployed about 2,500 people to Louisiana and states including Alabama, Florida, Georgia, Mississippi and Texas.

Oil explorers are bracing themselves for the storm and have already halted the equivalent of more than 1.2 million barrels of daily crude production.

After Ida comes ashore, it could also flood cotton, corn, soya bean and sugarcane crops, said meteorologist Don Keeney at commercial forecaster Maxar.

BLOOMBERG