Hurricane Harvey which ravaged US city of Houston at the weekend has claimed five lives.
It also left thousands of trapped residents desperately pleading for help after leaving much of the Texas city underwater.
Many residents have turned to social media with heart-breaking pleas for help.
Houston police department is asking civilians with boats to join them and assist with the more than 6,000 calls for rescues.
The storm has already dumped a historic 11 trillion gallons of water on the state of Texas – with another 27 inches of rain falling so far and another 23 inches expected to come within the next few days.
Experts said the aftermath of the catastrophic hurricane could equal the level of destruction of Katrina in 2005.
The Federal Emergency Management Agency (FEMA) also revealed it would take the area years to recover from the storm which is the worst this decade.
Houston, the nation’s fourth largest city, was told by its mayor not to evacuate and thousands were forced to seek higher ground due to the rising waters.
Members of the ‘Cajun Navy’ have set out from Louisiana with their private boats to help the rescue efforts in Texas after Hurricane Harvey flooded parts of the state.
The ‘Cajun Navy’ is a volunteer group of hundreds of boat owners who came together to help out their community during the Louisiana flood in the summer of 2016.
On Sunday, the Houston Police Department made a call for volunteers on Twitter asking people with boats to call a number and help the department out.
People frantically used Facebook to post photos of their dire situations and shared their location in hopes that they would be saved.
One woman posted on behalf of her friend with five children who were stranded on a roof.
The friend wrote: “Anybody please my friend is losing faith she feels like they running out of time.”
Since Thursday some parts of Houston have already received 25 inches of rain and some suburbs have gotten 27 inches.
The National Weather Service issued a forecast saying the city could get as much as 50 inches, which would be the highest amount ever recorded in Texas, adding: “The breadth and intensity of this rainfall is beyond anything experienced before.”
Houston Mayor Sylvester Turner said that as of 5pm on Sunday, Houston police and fire departments had received nearly 6,000 calls for rescues and had rescued more than 1,000 people.
Rescuers had to give top priority to life-and-death situations, leaving many affected families to fend for themselves. And several hospitals in the Houston area were evacuated due to the rising waters.
The destructive path of the hurricane began to take shape on Sunday, with a striking collection of aerial photographs laying bare its damage for the first time.
Highways lay submerged in water where abandoned cars bobbed alongside rescue boats taking residents to safety after 130mph winds and unprecedented floods swept through the southeast pocket of the state on Friday and Saturday.
Harvey has been downgraded from a Category 4 hurricane to a tropical storm but its threat is still imminent. Authorities are now fearing its second deadly phase – the floods.
Among the dead was a woman who died Saturday evening after getting out of her car when it drove into a flooded street in Houston.
The Houston Fire Department said a man died in floodwaters overnight Saturday into Sunday.
Two people reportedly died in Galveston on County Sunday. There was another death but the location was not made clear.
Mayor Turner said 22 aircrafts were working to help identify people stranded on roofs in Houston. Sixteen of those aircrafts are from U.S. Coast Guard.
In addition, 35 boats and 93 dump trucks were being used by the city for high water rescues.
The mayor also defended his decision not to order an evacuation.
“The decision that we made was a smart one. It was in the best interest of Houstonians. It was the right decision in terms of their safety… absolutely no regrets. We did what was the right thing to do,” Turner said.
And despite the massive “unprecedented” flooding, Turner argued that he stands by his decision not to evacuate, saying that it would have led to a worse outcome.
Turner added in a press conference: “If you think the situation right now is bad, you give an order to evacuate, you are creating a nightmare. Especially when it’s not planned.
“If you do it or attempt to do it and it’s not coordinated, not done right, you are literally putting people in harm’s way, and you’re creating a far worse situation.”