Francisco Sanches, spokesman for Harris County, where Houston is located, said if you're in this area, get yourself "out of harm's way" immediately, and there isn't much time to get out.
Houston officials said they will open two or three more mega-shelters to accommodate people who continue to arrive at the overflowing George R Brown Convention Centre seeking refuge from the flooding.
The Addicks and Barker reservoirs outside Houston hit record levels on Tuesday.
Fresno, TX, is part of Fort Bend County, less than 30 miles from Houston and just west of Brazoria County, which reported a levee breach and mandatory evacuations this morning, according to CNN. With rescues continuing, that number seemed certain to grow.
"This is something we've never seen before", he said.
The death toll from Harvey reaches 15 as President Trump and first lady Melania visit the disaster stricken state of Texas. Meanwhile, the tropical storm appeared to be gathering strength once again on the Gulf coast.
Volunteers and officers from the neighborhood security patrol help to rescue residents in the upscale River Oaks neighborhood after it was inundated with flooding from Hurricane Harvey on August 27, 2017, in Houston, Texas. Sylvester said the Coast Guard was taking more than 1,000 calls per hour.
Edmond Russo, a Corps deputy district engineer for Texas, made the comment at a Houston news conference Monday.
Mr Turner has inisisted that a mass evacuation of millions of people by vehicle was a greater risk than enduring the storm. A shortage of beds means some people will have to sleep on chairs or the floor.