Updated

One of the big questions facing Louisiana as Hurricane Ida drew closer to shore: How bad will the storm surge be?

The answer could be the difference between the type of flooding the state has seen with past hurricanes or "complete and utter devastation," according to a report.

While the greater New Orleans area is shielded to a degree by a massive levee protection system designed to limit flooding, residents in the Jefferson Parish communities of Jean Lafitte, Lafitte and Barataria rely on a levee of only seven-and-a-half feet, NOLA.com reported.

HURRICANE IDA ‘UNSURVIVABLE’ OUTSIDE LEVEE PROTECTION SYSTEM, LOUISIANA OFFICAL WARNS

A storm surge of 10 feet could result in hundreds of houses being flooded, while a storm surge of 15 feet could be catastrophic, Jean Lafitte Mayor Tim Kerner Jr. told the news outlet.

"Anything over 7½, 8 foot would be complete and utter devastation," Kerner said. "It'd be a historic storm in the worst possible way for the Town of Jean Lafitte, Crown Point, Lower Lafitte and Barataria, all of south Jefferson outside the levee protection."

"Anything over 7½, 8 foot would be complete and utter devastation. It'd be a historic storm in the worst possible way."

— Mayor Tim Kerner Jr., Jean Lafitte, Louisiana

Forecasters and local officials were expecting major roads to become impassable once Ida hits, so they were urging residents to leave Saturday for higher ground elsewhere in the state.

Jammed highways in the New Orleans area showed many were heeding the warnings.

Even if the storm surge level remains relatively low, at three to six feet, that could be enough to block many residents from receiving emergency response services for days, Patrick Harvey, director of homeland security and emergency preparedness in Plaquemines told NOLA.com.

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Whether Ida makes a direct hit on the area, causing potentially colossal damage, or makes a shift in direction, sparing some communities from the most extreme effects, one thing was for certain, said Police Chief Scooter Rosweber in Grand Isle.

"There’s no doubt in our mind that we’re going to flood," he said.