US Gulf coast braces as 'extremely dangerous' Hurricane Ida approaches

People evacuating ahead of Hurricane Ida clogged roads headed north on Saturday from the US Gulf Coast, with the strengthening storm set to hit New Orleans 16 years to the day after devastating Hurricane Katrina

"Ida is turning into a very, very dangerous storm," President Joe Biden said as it built to a Category 2 hurricane, packing 100 mile (160 kilometer) per hour sustained winds and heavy rain.

Traffic was heavy leaving New Orleans and other cities as officials warned locals to leave immediately or hunker down to ride out the storm.

"Ida is expected to be an extremely dangerous major hurricane when it approaches the northern Gulf coast on Sunday," the National Hurricane Center said.

Tropical storm-force winds are expected to hit the area Saturday afternoon, while Ida is forecast to slam into the coast as a powerful Category Four hurricane -- with winds up to 140 miles per hour -- late Sunday.

Louisiana Governor John Bel Edwards said Ida would be one of the most powerful storms to hit the state since the 1850s.

In New Orleans, Mayor LaToya Cantrell warned residents to take Ida with utmost seriousness.

"Time is not on our side," she told a briefing. "It's rapidly growing, it's intensifying."

Sunday is the 16th anniversary of Katrina, the devastating hurricane that flooded 80 percent of New Orleans, leaving 1,800 people dead and causing billions in damage.

Southern Louisiana was bracing for massive damage and flooding as the fast-intensifying storm roars northward after pummeling western Cuba.

"Extended power loss is almost certain," New Orleans homeland security director Collin Arnold told reporters Saturday. "I'm imploring you to take this storm seriously."

Biden said hundreds of emergency personnel had been sent to the region, along with food, water and electric generators.

Shelters were being prepared around the region, but Louisiana has been one of the hardest-hit states by the Covid-19 pandemic, and Biden urged anyone heading to a shelter to wear a mask and take precautions.

The National Weather Service is forecasting a "life-threatening storm surge" -- as high as 11 feet near New Orleans and 15 feet around the mouth of the Mississippi River -- when the hurricane makes landfall.

It warned of "catastrophic wind damage" and said Ida could spawn tornadoes.

Category Four is the second-highest on the Saffir-Simpson hurricane wind scale, with a minimum wind strength of 130 miles per hour.

Louisiana has declared a state of emergency in preparation for the storm.

The emergency declaration, approved by Biden, will expedite federal storm assistance to the southern state.

The hurricane made landfall late Friday in western Cuba as a Category 1 storm, packing winds near 80 miles per hour but causing mostly minor damage.

The dire warnings about Ida inevitably sparked memories of Katrina, Governor Edwards said in a briefing.

"It's very painful to think about another powerful storm like Hurricane Ida, making landfall on that anniversary," he said.

One big difference, he said, was the huge investment since then in an extensive storm protection system of levees, gates and pumps.

"Having said all that," he added, "this system is going to be tested... (but) we're going to get through this."

Meantime, a Category One hurricane named Nora was on a track threatening Mexico's central Pacific coast state of Jalisco, the NHC said. It warned of "life-threatening flash floods and mudslides."

Last week, a rare tropical storm struck the US northeastern seaboard, knocking out power, uprooting trees and bringing record rainfall.

Scientists have warned of a rise in cyclone activity as the ocean surface warms due to climate change, posing an increasing threat to the world's coastal communities.