Aug. 27 (UPI) -- Tropical Storm Harvey remained stalled over the Houston area Sunday, inundating most of the nation's fourth largest city with 2 feet of water and killing at least five people.
The storm, which made landfall as a Category 4 storm late Friday night, was downgraded to a tropical storm hours later, but it continued to overwhelm the region of 6.6 million people, including 2.3 million in the city of Houston. Most highways and roads were impassable except for boats, rivers were above flood stage, people were being rescued from their roofs and one of its two Level 1 trauma centers, Ben Taub, was being evacuated.
In all, the National Weather Service says 50 inches of rain may fall in some parts of the region.
"This event is unprecedented & all impacts are unknown & beyond anything experienced," the National Weather Service posted on Twitter.
The entire Texas Gulf Coast was under "life-threatening catastrophic flood warning" through early Monday morning by the National Weather Service in Houston-Galveston.
"It's catastrophic, unprecedented, epic -- whatever adjective you want to use," Patrick Blood, a NWS meteorologist, said to the Houston Chronicle. "It's pretty horrible right now."
Dr. Greg Postel, meteorologist and hurricane specialist for The Weather Channel, said the flooding "could be the worst flooding disaster in U.S. history."
Federal Emergency Management Agency Administrator Brock Long said it will take years for the region to recover.
"FEMA is going to be there for years," Long said on CNN's State of the Union. "This disaster is going to be a landmark event."
His agency was "pushing forward" teams for recovery housing and flood insurance programs.
Harris County Judge Ed Emmett estimated about 1,000 water rescues had taken place from homes and cars.
Capt. Kevin Oditt of the U.S. Coast Guard says their helicopters had rescued more than 100 people in Houston and have received over 500 calls for assistance.
The following dire warning was posted on Twitter at 4:16 a.m. Sunday:
"EMERGENCY MANAGEMENT HAS REQUESTED: IF HIGHEST FLOOR OF YOUR HOME BECOMES DANGEROUS...GET ON THE ROOF."
Houston Police Chief Art Acevedo warned people on Twitter said there were reports of people getting in to the attic to "not do so unless you have an ax or means to break through onto your roof."
Acevedo told said on Fox News the city's 911 system has been "overwhelmed" since Harvey struck.
"It breaks your heart," Acevedo said via a livestream on Twitter while standing in waist-high water in north Houston. "But, it's Texas, we'll get through it."
The Harris County Sheriff's Office said people should only use 911 in dire emergencies, as dispatchers struggled to keep up with the calls.
In Dickenson, about 30 miles south of Houston, residents of a nursing home were rescued from floodwaters.
Kim McIntosh, who lives in Florida, told CNN that her mother, who owns the La Bella Vita nursing home, took a photo of the residents sitting in several feet of water as they waited for help.
"They [were] waiting for helicopters or the National Guard," she said. "Most of these people are in wheelchairs and [on] oxygen," she said.
The Galveston Office of Emergency Management confirmed Sunday afternoon that it had rescued the residents from the facility.
"They were up to their waist" in water, said Ken Clark, a Galveston County commissioner.
Ben Taub Hospital, one of the largest public hospitals in Houston, was being evacuated, Harris County Judge Ed Emmett said at a news conference.
The hospital, which has 444 beds, was transferring patients to other facilities, he said.
Ben Taub is part of the multi-hospital Texas Medical Center a few miles from downtown.
William McKeon, president and chief executive of the Texas Medical Center, said the flood control systems had been activated. "Those submarine doors were locked yesterday afternoon when we started to see the rain."
It was difficult for people to reach the hospitals.
"Many outlying streets that are the channels to get to the medical center are flooded," McKeon said. "We can be dry and open but if you can't deliver patients to the medical center, that's our biggest concern."
The system's eight helicopters were working in outlying areas, but were not flying to the medical center because of high winds and tornado warnings.
Houston TranStar's updated list had 181 high-water locations on the roads, and both Houston airports are indefinitely closed while Metropolitan Transit Authority suspended all service.
The George R. Brown Convention Center in downtown Houston will be open for people who need shelter, but Houston Mayor Sylvester Turner urged people to stay home and stay calm.
Houston Independent School District officials canceled school for the whole week.
The heaviest rainfalls in the Houston area were 27.45 inches in Dayton and 27.42 in Santa Fe, according to the National Center for Environmental Prediction. South Houston had 24.54 inches.
The National Weather Service Houston says August is the city's wettest month on record with 25.5 inches of rainfall through 2 p.m., breaking June's 2001 when Allison hit the city.
"I know for a fact this is the worst flood Houston has ever experienced," NWC's Blood said. "Worse than [tropical storm] Allison. It's so widespread."
Maximum sustained winds decreased to near 40 mph and the center of the storm was 20 miles east of Victoria, according to National Hurricane Canter's 10 p.m. advisory. It was traveling 3 mph and was forecast to remain in the region through Wednesday.
On Sunday night, tornado warnings were issued for some parts of Houston as torrential rain returned after a lull during the day.
Winds and flooding weren't the only problems.
More than 300,000 people along the Gulf Coast remain without electricity since Friday, the utility, CenterPoint, reported. CenterPoint, which serves 2.4 million customers in Houston, said more than 97 percent still have power.
Exxon Mobil on Sunday said it was shutting its Baytown refinery, which is the second largest in the country. The refinery, about 25 miles east of Houston, can process up to 584,000 barrels of crude oil per day.
The U.S. Interior Department's Bureau of Safety and Environmental Enforcement estimated about 22 percent of natural gas production in the Gulf has been closed down. Nearly one-third of the nation's refinery capacity is in the Gulf of Mexico, including in Louisiana.
Four cruise ships won't be able to arrive Sunday at the Port of Galveston. About 20,000 passengers on three Carnival cruises and one Royal Caribbean ship were scheduled to disembark Saturday and Sunday morning but Harvey forced the Coast Guard to close the port.
Royal Caribbean's Liberty of the Seas headed to Miami to drop off passengers and Carnival's Valor, Freedom and Breeze made short stops in New Orleans to pick up additional food, water and fuel, Cruise Critic reported.
Even if the ships arrived Galveston Island, passengers wouldn't go far in vehicles because of flooded roadways.
For nearly one day, the one reported death was one person who died in a fire in Rockland.
The second death reported was in Houston, where a woman drove her vehicle into high water, city police said. The car had became inoperable or the water was too high to drive through. She got out of her vehicle and drowned.
A sixth death possibly linked to the storm was in La Marque where a 52-year-old homeless man's body was spotted in a Walmart parking lot. It wasn't unclear if his death was flood-related.
Aransas County Sheriff Bill Mills said additional fatalities were feared in Rockport. An estimated 5,000 residents didn't evacuate from the storm, which landed between Port Aransas and Port O'Connor.
Rockport Mayor Charles Wax told CNN emergency workers were going house to house to check on residents and assess damage.
"There's been widespread devastation," Wax said. "We've already taken a severe blow from the storm, but we're anticipating another one when the flooding comes."
Bill Terry, Information Officer for Texas A&M Forest Service Incident Management Team, said at a press conference in Rockport that "this area is totally void of any functioning infrastructure."
Some cellphone service was regained overnight but there is no running water, and issues with the sewer system, Terry said.
Residents had evacuated to San Antonio -- about 200 miles from Houston. About 950 people were in shelters in the city, city fire department spokesman Woody Woodward told CNN.
Cook Children's Hospital in Fort Worth took in 10 critically ill babies from a hospital in Corpus Christi.
Abbott praised the efforts of FEMA.
"I've got to tell you, I give FEMA a grade of A+, all the way from the president down. I've spoken to the president several times, to his Cabinet members, such as secretary of homeland security, such as the administrator of FEMA, such as Tom Price, the secretary of health and human services," Abbott said in an interview with Chris Wallace on Fox News Sunday. "All across the board, from the White House to the federal administration to FEMA, they've been very helpful."
"Great coordination between agencies at all levels of government. Continuing rains and flash floods are being dealt with. Thousands rescued," Trump posted on Twitter.
On Friday before the storm made landfall, Trump signed a disaster declaration to make funds available to Texas.
Trump plans to travel to Texas on Tuesday, White House press secretary Sarah Huckabee Sanders said. But the president will avoid the most hard-hit areas and is learning toward visiting San Antonio, sources told CNN.