- Video report by ITV News Washington Correspondent Robert Moore
Thousands of people required rescuing in and around Houston after dramatic flooding submerged many parts of the city in the wake of Hurricane Harvey.
Floodwaters up to neck-height in some areas swamped Houston after Harvey, now downgraded to a tropical storm, dumped more than two feet of rain over the weekend.
Hundreds of people could be seen taking refuge on rooftops as emergency services were overwhelmed by calls for rescue.
Boats and helicopters were deployed to bring people to safety, including a group of care home residents pictured trapped in a flooded lounge.
Flooding forced shut both of the city's major airports on Sunday, while authorities also planned to evacuate Houston's main public hospital.
And torrential rain is expected to batter Texas for days to come, with forecasters anticipating up to 50 inches of precipitation.
Texas Governor Greg Abbott issued a special plea for people to head to high ground as authorities continued to deal with the emergency.
He revealed that about 250 roads and motorways had been closed in Texas and that he had made a federal disaster declaration for 19 counties that was granted by President Donald Trump.
His comments came as weather experts described the devastating flooding as "unprecedented" and "unknown and beyond" anything previously experienced.
By the end of Sunday, many main roads resembled rivers, with hundreds of people being rescued from their homes on volunteer boats.
In Galveston County alone, up to 1,200 people had to be rescued by emergency services.
Rescues were launched by air as well, operating in some areas where flood water reached up to people's necks.
Drivers had to be helped from vehicles submerged by water, while pictures showed elderly residents trapped in a flooded care home living room in Dickinson, Texas.
Dramatic footage later showed the group of pensioners being carried to safety in a combined boat and helicopter operation.
Texans had been warned to expect "catastrophic" flooding and storm surges as Hurricane Harvey approached on Friday.
Two people people were killed over the weekend as the storm raged.
One person was killed in Aransas County in a fire as Harvey hit, while a second person was killed by flooding in Harris County.
Winds of up to 130mph slammed many parts of coastal Texas, before being downgraded from a category four storm to a tropical storm by Saturday afternoon.
But nobody could anticipate the destruction wreaked by the flood waters, leaving many parts of the city completely submerged.
President Donald Trump declared an official disaster in the area, while he later described Harvey as a "500 year flood" in a series of tweets.
The president also reported that experts had "never seen" such significant flooding from a storm.
Trump is expected to travel to Texas on Tuesday.