Gov. John Bel Edwards spoke at a news conference alongside FEMA administrator Craig Fugate, saying "well over" 20,000 people have been rescued since the flooding began Friday. His office later increased the figure to more than 30,000 rescues.
Beginning Friday, a torrent of about 2 feet of rain inundated the southern part of the state over a 48-hour period, and days later many homes and businesses were still underwater.
While some areas were entering recovery mode, the governor warned new places downstream could see flooding and that officials are still in search and rescue mode.
"I don't know we have a good handle on the number of people who are missing," the governor said.
Some residents returned to their flood-damaged homes for the first time Tuesday and found a soggy mess.
David Key used a small boat to get to his house in Prairieville and said it had taken on 5 inches of "muddy nasty bayou water." There were fish and thousands of spiders. And mold has started to set in.
"I'm not going to lie, I cried uncontrollably," he said. "But you have to push forward and make it through. Like everybody says, you still have your family."
The extent of damage was coming into clearer view. About 40,000 people had signed up for FEMA assistance and eight more parishes were added to the federal disaster declaration, bringing the total number to 12.
In Livingston Parish, one of the hardest-hit areas with about 138,000 people, an official estimated that 75 percent of the homes were a "total loss."
But Lori Steele, spokeswoman for the Livingston Parish Sheriff's Office, was upbeat, saying the rescues taking place now are less of a "life-saving nature" and more to help people who were running low on supplies in flooded areas. As the main roads drain, emergency crews were going to be able get hot meals, water and medical supplies to the 25 shelters in the parish.
"We're tired but today's a good day," she said.
Rivers and creeks were still dangerously bloated in areas south of Baton Rouge as people filled sandbags there to protect their houses, bracing for the worst as the water worked its way south. In Ascension Parish, officials said some small towns have already been inundated.
The governor said more than 8,000 people were in shelters, but the number was constantly fluctuating as people arrive and leave.
The slow-moving, low-pressure system that dumped more than 20 inches of rain on some parts of Louisiana was crawling into Texas, but the National Weather Service warned the danger of new flooding remained high due to the sheer volume of water flowing toward the Gulf of Mexico.
In and around Baton Rouge, many were anxious to check on damage. But a police officer at one Baton Rouge area roadblock warned Jack Miller that the 60-year-old was risking arrest if he tried to drive a boat on a trailer down a stretch of the highway down to just two lanes.
"I'm trying to get back to my home and rescue my cat," Miller said.
The eighth storm-related death was the accidental drowning of a 66-year-old man whose body was found in the Sherwood Forest area, which has been a site of severe flooding, state officials said.
Karla and Johnathon McDaniel waded through chest-deep water to revisit their home they fled late Saturday night but the water was too deep to get inside.
On their way out, the McDaniels stopped to gawk at a monster truck revving its engine in a failed attempt to free a National Guard vehicle mired in a muddy ditch. It was a welcome moment of levity after days of worry around the state's southeast, which saw thousands of water rescues.
Julee Doiron, 56, and a friend walked down the road to a flooded storage facility where she has a valuable record collection. She felt fortunate the flooding stopped a block short of her home, but she owns a couple of water-damaged rental properties that aren't covered by flood insurance.
"None of these places are in a flood zone," she said. "Why buy it if you don't need it? My agent didn't recommend it to me."
In a state more accustomed to hurricanes, forecasters said the rains were nearly off the charts in intensity. Meteorologist Ken Graham of the National Weather Service's office in Slidell, near New Orleans, said forecasters had alerted people days ahead of the rain. Yet the forecasts Thursday were for 8 inches of rain, with higher totals expected in some areas.
One town, Zachary, received more than 2 feet of rain in a 48-hour period that ended Saturday morning. Another, Livingston, got nearly 22 inches over the same stretch. Rivers in the region reached historic highs — occasionally shattering old records dating to 1983 floods.