Millions of Gulf Coast residents are dealing with the ghosts of Hurricane Katrina and the real-and-present danger of Hurricane Isaac, which made landfall Tuesday night in southeastern Louisiana.

River waters rising fast

Near Biloxi, Mississippi, shrimpers and other fishermen sought shelter on the Tchoutacabouffa River, 15 miles from the Gulf of Mexico.

While they appeared safe, the same couldn't be said for land and property along the water.

By 2 p.m. CT, before much rain had fallen, the river was already several feet higher than normal, resident and CNN iReporter Jim Yelverton said.

And that was at low tide.

"It's rising a lot faster than anyone expected," said Yelverton, who expressed fears that things could get much worse at high tide Wednesday morning. "What may happen is that the water surge will get to the structures and tear them apart."

'Katrina is not a taboo subject'

By midafternoon Tuesday, 400 residents of Plaquemines Parish, southeast of New Orleans, were calling a shelter in Belle Chasse home.

"It's a mix of people," said Gina Meyer, superintendent of emergency medical services with the parish. "You treat them like family. You ask how they are doing and sit down and talk with them. These people are so resilient."

Many of the evacuees endured Hurricane Katrina seven years ago.

"Katrina is not a taboo subject with us. It is reality," said Meyer. "They are not afraid to talk about it, (but) they don't beat a dead horse."

The evacuees, who are sleeping on cots, are "consistently thankful," Meyer said.

Town on Louisiana barrier island empties

Grand Isle in Jefferson Parish was transformed Tuesday into a tropical ghost town -- its mayor saying that all but 30 people heeded evacuation orders and headed to dryer locales.

By afternoon, the only evident activity was among a few emergency personnel riding around town. And as the day wore on, Mother Nature introduced herself in a big way.

The barrier island was lashed by strong winds paired with heavy rains, which then subsided. A few minutes later, another such band would move through -- each successive one typically stronger than the next.

By early Tuesday evening, winds gusted past 60 mph, and they were only climbing higher.

'Where are the people who lived here prior to Katrina?'

CNN iReporter Eileen Romero lost everything in 2005 to Hurricane Katrina.

She still lives in New Orleans, now in a different neighborhood and in a house built in 1908.

Romero went out Tuesday to take photographs.

"I am not seeing people real concerned to be honest," she said. "I think there is a false sense of security. Everybody talks about how we party all the time. When hurricanes are coming, people have hurricane parties."

While she didn't believe Isaac would cause near the damage wrought by Katrina, the student said she was nervous.

"Everything reminds you of Katrina. When the wind howls, I think of Katrina. I don't think of Isaac."