At least 30 people have been confirmed dead in Hurricane Harvey.
Experts have also estimated the damage caused so far by Harvey to be $160 billion.
But the casualty figure is expected to rocket as the waters recede and emergency services begin recovering victims in what experts are now describing as the worst natural disaster in US history.
The impact of the hurricane worsened on Tuesday night as even rescue shelters housing terrified evacuees who have lost their homes filled up with flood water.
At the Bob Bowers Civic Center in Port Arthur, evacuees were forced to wait in the stands as water washed over the floor and sent their Red Cross cot beds and chairs floating.
They were taken to Carl Parker Center at Lamar State College where they now join hundreds of others who have been displaced. It is not clear how many people were in the first shelter when the floods crept in on Tuesday night.
More than 30,000 people are in bursting shelters as floods continue to swamp Houston after the heaviest rainfall in US history. Countless more are taking cover in the homes of friends and family whose houses are, for now, safe from the floods.
The water continues to rise, sparking electrical fires in abandoned homes and threatening to drown anyone who has been unable to escape.
More than 50 inches of rain has fallen in parts of Houston – the heaviest rainfall in US history – and the downpours continue.
Joel Myers, the founder of the AccuWeather service, described it as the “worst natural disaster in US history” on Wednesday and estimated the damage to be $160 billion – the same amount as that caused by Hurricanes Katrina and Sandy combined
Anyone who is still in need of rescue is being asked to get on high ground and wave white towels or sheets to make themselves visible. Overwhelmed authorities are also asking anyone with boats to help in the rescue efforts.
Many in Port Arthur and Beaumont are trapped on their roofs awaiting rescue.
On Tuesday, Houston’s Police Chief, Art Acevedo, painted a grave picture of the devastation. “I’m worried about how many bodies we’re going to find. I’m just hoping we find the bodies,” he said, as his officers continued to focus their efforts on saving their living rather than retrieving the bodies of the dead.
Harvey made landfall in Texas on Friday and ravaged the southeast coast before moving back off shore where it has thundered on for days.
It returned to land on Wednesday, arriving on the state lines of Texas and Louisiana at 5am and bringing 10 inches of rain to Louisiana where preparations have been underway for days in anticipation of the deadly storm.
Rescue teams and volunteers continue rescuing stranded residents from the waters.