The unrelenting storm unleashed its wrath on a wide swath east of Houston, leaving thousands stranded in flooded homes and forcing the evacuation of a nursing facility and even an emergency shelter where residents had sought refuge.

"Our whole city is underwater right now but we are coming!" Port Arthur Mayor Derrick Freeman posted Wednesday on Facebook. "If you called, we are coming. Please get to higher ground if you can, but please try (to) stay out of attics."

My uncles have been rescuing people in Port Arthur for 24hrs! So blessed to have such a helpful family who help others in times like this! pic.twitter.com/O2qIVGHqxR

At least 37 deaths related to Hurricane Harvey and its aftermath have been reported in Texas. One of them, Houston police Sgt. Steve Perez , drowned while trying to get to work.

"To those Americans who have lost loved ones, all of America is grieving with you and our hearts are joined with yours forever," President Donald Trump said in Springfield, Missouri.

The storm left record-setting rain in Harris County -- which saw 19 deaths -- before unleashing 15 inches in the Beaumont area, Texas Gov. Greg Abbott said.

"While there may still be flooding, the good news is there shouldn't be any rain in the region for the next several days," said CNN Meteorologist Taylor Ward.

Evacuees at the Bob Bowers Civic Center in Port Arthur face flooding again as waters rise at the shelter.

Misery in Houston

While heavy rains have ended in the Houston area, more danger looms.

Emergency workers and throngs of volunteers went door to door for a fifth day Wednesday, trying to rescue victims of the flood. Houston Police Chief Art Acevedo said authorities have received 60,000 to 70,000 calls for help.

"We just pray that the body count ... won't rise significantly." Acevedo said.

The US Coast Guard is searching for two civilian rescuers who were swept away after their boat capsized Tuesday night, the Harris County Sheriff's Office tweeted Wednesday.

Three volunteers were trying to cross Cypress Creek when their boat crashed and capsized, sending all three under a bridge. One of the volunteers was found clinging to a tree.

JUST WATCHED Torrential downpour submerges parts of Houston Replay More Videos ... MUST WATCH Torrential downpour submerges parts of Houston 01:06

About one-third of the Houston area is covered in water. And it's unclear exactly how many people still need to be rescued, Texas Military Department spokesman Lt. Col. Travis Walters said.

For the first time since the weekend, authorities said, the flooding in Houston is slowly receding in some areas.

The Houston Astros announced they will play a doubleheader at home on Saturday against the New York Mets. The team played the Texas Rangers in St. Petersburg, Florida, earlier this week because of the hurricane.

Houston Mayor Sylvester Turner said the home game will provide "a much needed boost for our city" and offer residents "some aspect of normal life."

But dangerous flooding will continue from Houston all the way into southwestern Louisiana for the rest of the week, the National Weather Service said.

Houses built 'inside a lake' could degrade

Controversy has surrounded the placement of houses near Houston's Barker and Addicks reservoirs, especially since floodwater overflowed the latter.

Residents evacuate their homes Tuesday near the Addicks Reservoir in Houston.

"They allowed them to build homes inside the reservoir. And these homes are flooded -- 2,500 homes are flooded, some of them up to 5 feet deep," CNN meteorologist Chad Myers said Wednesday. "They built homes inside a lake."

And those homes "will be inundated for several weeks," said Jeff Lindner with Harris County Flood Control.

"The closest comparison that I can draw to those homes ... is Hurricane Katrina," Lindner said.

"When water sits in a house for several weeks, the house begins to degrade."

Lindner said those residents will be able to return after several weeks, but "we are not sure what the condition of those homes are going to be."

He also said it's unclear whether rebuilding homes in the same area will be allowed.

Louisiana weathers Harvey, Texas 'taking it on the chin'

Louisiana was largely spared from Harvey's wrath on Wednesday.

"While things are still serious and there is a long way to go, we ... have fared much better than we'd feared might be the case, but our neighbors are still taking it on the chin," Gov. John Bel Edwards said. "In Texas, we're going to do everything we can do to be good neighbors to them."

Edwards requested a federal disaster declaration be extended to seven additional Louisiana parishes.

Harvey is still threatening to dump an additional 3 to 6 inches of rain from northern Louisiana into western Kentucky, forecasters said. It weakened over land and fizzled to a tropical depression Wednesday night, with winds of 35 mph.

New Orleans Mayor Mitch Landrieu said volunteers helped New Orleans recover after Katrina and they will do the same for Texas residents affected by Harvey.

New Orleans officials announced a fundraiser to help the residents of Houston and other flooded Texas cities recover from Harvey.

"No city was more welcoming for the citizens of New Orleans than the people of Houston," Landrieu said. "And our heart breaks for them as they go through their trying to times."

More rescues, mother dies

In Beaumont, rescuers Tuesday afternoon came upon a toddler in a pink backpack clinging to her mother's body in floodwaters about a half mile from their car. The mother was getting out of her car when she stepped into a canal, Mayor Becky Ames said.

The girl was in stable condition with hypothermia.

"Had we been a few moments later, they would have been swept underneath (a trestle) and our boats wouldn't have been able to get them," Haley Morrow, spokeswoman for the Beaumont Emergency Management Office, told CNN on Wednesday.

"A true testament of a mother who put her own life at risk and sacrificed her life to save her child. That was devastating."

In Port Arthur, about 90 miles east of the devastated Houston area, the deluge was so severe that floodwaters overwhelmed the Bob Bowers Civic Center, which was serving as a shelter. It was evacuated Wednesday after taking on water overnight, according to volunteer Ana Platero.

Cots where people slept the night before floated on 2 feet of water on Wednesday as people waited on tables or sat on elevated bleachers to be evacuated to a nearby middle school.

At Lake Arthur Place, a nursing home in Port Arthur, rescue workers evacuated up to 74 bedridden patients after an altercation involving relatives who tried to take out loved ones on their own, CNN affiliate KTRK reported.

All residents were taken to local hospitals in Beaumont, the nursing home operator said.

Some Port Arthur residents sought shelter in a bowling alley.

Cynthia Harmon told CNN by phone that she was trapped with her two sons and two grandsons in the attic of her Port Arthur home. They began waiting for rescuers at midnight Tuesday and had run out of food and water by Wednesday afternoon.

"I didn't think the water was going to rise like that," she said. "I've never been in anything like this."

The family was rescued later on Wednesday.

Police made an appeal for volunteers to bring boats and help.

"Rescue boats welcome in Port Arthur to assist emergency personnel," the police department posted on Facebook. The city asked anyone trapped to hang a white towel, sheet or shirt outside to alert rescuers.

Photos: Hurricane Harvey slams Texas Downtown Houston is seen behind the flooded Buffalo Bayou a few days after Hurricane Harvey came ashore in August 2017. The Category 4 storm caused historic flooding. It set a record for the most rainfall from a tropical cyclone in the continental United States, with 51 inches of rain recorded in areas of Texas. An estimated 27 trillion gallons of water fell over Texas and Louisiana during a six-day period. Hide Caption 1 of 22 Photos: Hurricane Harvey slams Texas NASA astronaut Jack Fischer photographed Hurricane Harvey from the International Space Station. Hide Caption 2 of 22 Photos: Hurricane Harvey slams Texas Steve Culver comforts his dog Otis in the hurricane aftermath. Harvey destroyed most of his home in Rockport while he and his wife were there. Hide Caption 3 of 22 Photos: Hurricane Harvey slams Texas Houston police officer Daryl Hudeck carries Catherine Pham and her 13-month-old son, Aiden, after rescuing them from floodwaters. Hide Caption 4 of 22 Photos: Hurricane Harvey slams Texas A damaged home is seen in the Key Allegro neighborhood of Rockport. Hide Caption 5 of 22 Photos: Hurricane Harvey slams Texas A car is submerged by floodwaters on a freeway near downtown Houston. Hide Caption 6 of 22 Photos: Hurricane Harvey slams Texas Melani Zurawski cries while inspecting her home in Port Aransas, Texas. Hide Caption 7 of 22 Photos: Hurricane Harvey slams Texas A graveyard is flooded in Pearland, Texas. Hide Caption 8 of 22 Photos: Hurricane Harvey slams Texas Soldiers with the National Guard patrol Rockport, looking for residents trapped in their homes. Hide Caption 9 of 22 Photos: Hurricane Harvey slams Texas Evacuees are loaded onto a truck in Houston. Hide Caption 10 of 22 Photos: Hurricane Harvey slams Texas People push a stalled pickup through a flooded street in Houston. Hide Caption 11 of 22 Photos: Hurricane Harvey slams Texas Rockport residents return to their destroyed home. Hide Caption 12 of 22 Photos: Hurricane Harvey slams Texas Rescue boats fill Tidwell Road in Houston as they help flood victims evacuate the area. Hide Caption 13 of 22 Photos: Hurricane Harvey slams Texas People wait to be rescued from their flooded home in Houston. Hide Caption 14 of 22 Photos: Hurricane Harvey slams Texas Volunteers in Dallas organize items donated for hurricane victims. Hide Caption 15 of 22 Photos: Hurricane Harvey slams Texas When Harvey slammed the Texas coast and flooded much of Houston, volunteers sprang into action. Some came from as far away as the Florida Everglades, boats in tow, ready to rescue people trapped in their homes. Hide Caption 16 of 22 Photos: Hurricane Harvey slams Texas Larry Koser Jr. and his son Matthew look for important papers and heirlooms inside a flooded home in Houston. Hide Caption 17 of 22 Photos: Hurricane Harvey slams Texas Members of the National Guard rest at a furniture store in Richmond, Texas. Hide Caption 18 of 22 Photos: Hurricane Harvey slams Texas Volunteer rescue workers help a woman from her flooded home in Port Arthur, Texas. Hide Caption 19 of 22 Photos: Hurricane Harvey slams Texas This aerial photo shows flooded residential neighborhoods in Houston. Hide Caption 20 of 22 Photos: Hurricane Harvey slams Texas Tammy Dominguez and her husband, Christopher, sleep on cots at the George R. Brown Convention Center, where thousands of people were taking shelter in Houston. Hide Caption 21 of 22 Photos: Hurricane Harvey slams Texas An elderly patient waits to be rescued from the Gulf Health Care Center in Port Arthur. The facility was evacuated with the help of first responders and volunteers. Hide Caption 22 of 22

The disaster in Port Arthur is part of Tropical Storm Harvey's devastating encore. Harvey made landfall once again Wednesday morning, slamming into the Louisiana coast near the Texas border.

26 inches in 24 hours

Harvey has broken the US record for rainfall from a single storm, CNN senior meteorologist Dave Hennen said. It has dumped almost 52 inches of rain in parts of Texas.

The coastal cities of Beaumont and Port Arthur got pummeled with 26 inches of rain in 24 hours.

"Life-threatening flash flooding continues in far east Texas around Beaumont and Port Arthur," Hennen said.

Port Arthur, a city of about 55,000, is in exceptional danger because water from Beaumont is expected to flow toward it.

In Beaumont, a man who accidentally drove a truck into a flooded ravine that looked like a street was rescued by CNN correspondent Drew Griffin, producer Brian Rokus and photographer Scott Pisczek on Wednesday. "I want to thank these guys for saving my life," said the driver, Jerry Sumrall.

In Woodville, a town north of Beaumont, US Rep. Brian Babin was trapped for part of Wednesday at home with members of his family after a creek overflowed.

"I'm in my home in Tyler County, and we could not get out unless a helicopter plucks me out or I get my boat and launch it," the Texas Republican told CNN by phone early in the day. "We're fine. These waters are going to recede hopefully sometime this evening."

On Wednesday afternoon, a US Navy helicopter plucked seven people from floodwaters.

'We help each other out'

Strangers from across the country descended on Texas and braved treacherous floodwater to evacuate victims.

JUST WATCHED CNN crew helps rescue man from truck Replay More Videos ... MUST WATCH CNN crew helps rescue man from truck 02:05

Tom Dickers is among those who came hauling boats from Dallas and San Antonio.

"This is what Texans would do. We help each other out," Dickers said.

At least 9,000 to 10,000 people have been rescued in the Houston region by first responders. Volunteers said they have helped as many as 400 in one day.

Some would just "come crying, just wanting help," volunteer Bobba Bedri said. "I just felt like I had to get more people out, keep going and keep going."

CLARIFICATION: Harvey made its first landfall at 10 p.m. local time Friday, initially striking a barrier island near Port Aransas, Texas, before moving onto the US mainland two hours later near Copano Bay, Texas. After re-emerging into the Gulf of Mexico on Monday, it made another landfall Wednesday in Louisiana.