Granger, police said, was injured while trying to protect her 15-month-old son, Tyreik, as the twister roared through her neighborhood.
Authorities said she died at the hospital after being dug out from under wreckage of her home in this town of about 8,500 residents.
About 1,500 of those residents were allowed back into their neighborhoods on Monday morning after two nights of curfew while the area was cleared of dangerous debris and leaking gas lines were repaired.
Damage from the storm affected about a five-mile path through the heart of the city.
Hardest hit was a 10-block section where entire houses were destroyed, roof damage was prevalent and many porches and out buildings were simply gone.
Fire Chief Barry Granger, whose people were working around the clock, said the disaster is the worst he has ever seen.
“We have had hurricanes, but we have never had anything like this,” Granger said.
Acadia Parish Sheriff's Office spokewoman Maxine Trahan said she estimated more than 100 homes were destroyed or so badly damaged they are no longer livable.
She said the hardest hit area is also one of the city’s poorest.
Gov. Bobby Jindal visited the area on Sunday and said a FEMA team will be on the ground Wednesday.
Jindal said a team from his office has been in the city since the storm and a team from FEMA is expected Wednesday.
He said, depending on what FEMA finds, uninsured residents may be able to get up to $30,000 in federal assistance or qualify for up to $2 million in low-interest loans to rebuild.