New evidence has emerged suggesting the monster floods that devastated Grantham four years ago was a man-made disaster that could have been avoided, 60 minutes reports.
Helicopter flight logs from the Nine News chopper add to a growing inventory of evidence that locals say was ignored by the commission set up to investigate the causes of the 2011 Queensland floods.
Grantham, in the Lockyer Valley, was described as a "war scene" and "completely and utterly devastated" by the January 10 flood that killed 12 people in the town of 300 residents.
Relying heavily on the expert evidence of hydrologists, the commission's final report concluded that the Grantham quarry wall might have lessened the impact of the floods.
But first-hand accounts from residents have long contradicted the commission's findings, claiming a powerful inland tsunami hit the town when the quarry burst.
The chopper's log supported eyewitness accounts as well as the findings of an independent report spearheaded by The Australian journalist Nick Cater.
"The commission report got it flat wrong," Mr Cater told 60 minutes.
The commission concluded that a wall of flood water hit Grantham between 3.15 and 3.30pm, which fit the timeline of events that suggested the overflowing river upstream was the cause of the devastation.
Gratham inundated with water after monster floods in 2011.
But the Nine News chopper, which flew over the town in the Lockyer Valley and recorded the wall of water ripping through the town didn't leave Brisbane until 4.16pm.
During that missing hour, water was building up behind the quarry wall up stream owned by concrete giant Wagners, according to Cater's report commissioned by The Australian.
The quarry stopped the water running its natural course along the river, forcing it to build up over the course of the hour, Cater said.
When the quarry burst it caused a giant inland tsunami that wiped out the town.
"It was man-made intervention. It was no act of god," Cater told 60 minutes.
"You can imagine it's like a dam bursting … this enormous volume of water taking everything in its path with tremendous force," Cater told 60 minutes.
"Whole houses demolished, one house exploded … nothing can survive," he said.
Queensland Premier Annastacia Palaszczuk announced a second commission of inquiry into the Grantham flood earlier this month.
The second inquiry will investigate whether the landscape, including the quarry, contributed to the flood.
"Residents of Grantham and their Mayor Steve Jones have been calling for this inquiry and we have been listening," she told the Queensland House of representatives when she launched the inquiry.
"The people of Grantham have suffered through a horrific, terrifying, fatal event they deserve and require further closure.
"They are determined that the deaths of their friends and neighbours and family members on that day will not be in vain," she said.
The inquiry will run until August 31 to allow independent modelling to take place.