The main shelter set up in Houston for people evacuated after Storm Harvey, is already getting full, with officials warning that up to 30,000 people may need emergency accommodation. Close to 6,000 are already in one shelter or another in the besieged city.

The facility established by the Red Cross inside the George Brown Convention Centre is designed to hold 5,000 people. Yet there are already more than 2,600 people taking shelter there from the torrential rain, having either been rescued from their homes or walked to safety themselves.

“We are not out of the woods yet,” Elaine Duke, the acting Homeland Security secretary said, with President Donald Trump later promising – ahead of a visit to Texas on Tuesday – that the region would get the money and services required to deal with damage and the flooding caused by the "historic" rain that continues to fall.

More than 5,000 people are already in shelters (AP)

The storm is said to have caused a number of deaths, with the death toll expected to rise. A spokeswoman for Harris County coroner's office – where Houston is located – said there were at least six deaths there, while a woman in neighbouring Montgomery County was apparently killed after a tree fell onto her trailer home.

On Monday lunchtime, Houston Police Chief Art Acevedo said his officers had received 6,000 emergency calls and rescued 2,000 people in the past day.

Yet, he said there were still more people who still needed to be rescued, and he said there were about 185 requests still outstanding for critical rescues. The Independent accompanied one volunteer team that rescued a family of three, among them two young children. The little girl told how her father had help lots of people in their neighbourhood using a kayak. "My dad's very brave," he said.

While rain eased overnight and flood levels dropped dramatically, emergency teams – joined by hundreds of volunteers and an Armada of boats, were back on those streets that were still flooded and where they believed people still needed to be rescued.

Andrew Buncombe speaks to rescuers amid Hurricane Harvey on Facebook Live

Texas Governor Greg Abbott warned Houstonians to brace for a long period of disruption.

“We need to recognise this is going to be a new and different normal for this entire region,” Mr Abbott said after touring the damaged coastal city of Corpus Christi.

Harvey was expected to remain over Texas' Gulf Coast for the next few days, dropping another 15 to 25 inches (38-64 cm) of rain, with threats of flooding extending into neighbouring Louisiana.

Harvey's centre was 137 kilometres (85 miles) south-southwest of Houston on Monday afternoon and forecast to arc slowly toward the city through Wednesday, with the worst floods expected later that day and on Thursday.

The aftermath of Hurricane Harvey Show all 19 1 /19 The aftermath of Hurricane Harvey The aftermath of Hurricane Harvey A tattered U.S. flag damaged in Hurricane Harvey, flies in Conroe, Texas Reuters The aftermath of Hurricane Harvey Lisa Rehr holds her four-year old son Maximus, after they lost their home to Hurricane Harvey, as they await to be evacuated with their belongings from Rockport, Texas Reuters The aftermath of Hurricane Harvey People line up for food as others rest at the George R. Brown Convention Center AP Photo/LM Otero The aftermath of Hurricane Harvey Volunteers with The American Red Cross register evacuees at the George R. Brown Convention Center Reuters/Nick Oxford The aftermath of Hurricane Harvey Soldiers with the Texas Army National Guard help the residents of Cyprus Creek Reuters The aftermath of Hurricane Harvey Residents wade through floodwater Reuters/Nick Oxford The aftermath of Hurricane Harvey Residents walk along the flooded roadway of Texas 249 as they evacuate their adjacent neighborhoods EPA The aftermath of Hurricane Harvey A man floats past a truck submerged on a freeway flooded by Tropical Storm Harvey on Sunday AP The aftermath of Hurricane Harvey People are rescued by airboat as they evacuate from flood waters from Hurricane Harvey in Dickinson, Texas Reuters The aftermath of Hurricane Harvey James Archiable carries his bike through the flooded intersection at Taylor and Usenet near downtown Houston, Texas EPA The aftermath of Hurricane Harvey A massive sinkhole opened up on a motorway in Rosenburg, a city 25 miles southwest of Houston, Texas Rosenberg Police The aftermath of Hurricane Harvey People are rescued from flood waters from Hurricane Harvey in an armored police mine-resistant ambush protected vehicle in Dickinson, Texas Reuters The aftermath of Hurricane Harvey People are rescued from flood waters from Hurricane Harvey on a boat in Dickinson, Texas Reuters The aftermath of Hurricane Harvey Evacuees are airlifted in a US Coast Guard helicopter after flooding due to Hurricane Harvey inundated neighborhoods in Houston, Texas Reuters The aftermath of Hurricane Harvey Evacuees leave a US Coast Guard helicopter after being rescued from flooding due to Hurricane Harvey in Houston, Texas Reuters The aftermath of Hurricane Harvey Residents look on at a submerged motorway during a break in the rain in Houston, Texas EPA The aftermath of Hurricane Harvey People photograph the submerged motorway interchange EPA The aftermath of Hurricane Harvey Debris lies on the ground after a building was destroyed by Hurricane Harvey in Aransas Pass, Texas AP The aftermath of Hurricane Harvey Dominic Dominguez searches for his boat in a boat storage facility that was heavily damaged by Hurricane Harvey near Rockport, Texas EPA

In some of the city’s neighbourhoods, floodwaters reached the roof lines of single-story homes and people could be heard pleading for help from inside. While much of Houston has electricity and while several areas have escaped any damage, America’s fourth largest was barely moving. With nearly two feet of rain still expected, authorities worried whether the worst was yet to come.

The Army Corps of Engineers said it had been forced to open reservoirs overwhelmed by Harvey. The move was aimed at protecting the city centre business district, but risked flooding thousands more homes.

In a sign of the ongoing concern, Mr Abbott, who was among those who had suggested Houston residents be told to evacuate before the storm hit, said he was activating all of the the national guard – nearly 12,000 in total.

Houston Mayor Sylvester Turner told the media: “The goal is rescue. That’s the major focus for today.”

At the White House, Mr Trump told people suffering through Harvey and the resulting flooding that “you're going to have what you need and it's going to go fast”.

Mr Trump added that he has spoken with members of Congress and “everybody feels for” people in the storm's path. The President also told flooding victims via a press conference on Monday that “we are 100% with you”.

He added: “We will get through this. We will come out stronger and believe me we will be bigger, better, stronger than ever before.”

With the Red Cross scrambling to set up more emergency shelters and appealing to restaurants who were able to spare any food to make it available, it is not just Houston and the surrounding areas that have been impacted.

Wendy Rom, 24, was among those taking refuge at the centre with her husband and her 18-month old daughter.

“The water was high, entering our house, so we moved to the second floor but they started evacuating the neighbourhood so I came with my whole family,” she told Reuters.

With Harvey shifting course all of the them, creating bands of weather that frustratingly turn from rain to sun in a matter of minutes, the heavy rain has also moved eastwards and moved into neighbouring Louisiana.

“The worst is yet to come,” said Louisiana Governor John Bel Edwards, with Mr Trump having approved an emergency declaration for Louisiana – as he did for Texas on Friday – to help with releasing funds.