Updated at 1:30 a.m. ET Monday
At least two people have been killed as the Houston area continues to be inundated by torrential rain and catastrophic flooding from Tropical Storm Harvey, which officials called an "unprecedented" weather event that has left thousands of homes flooded, stranding some people and overwhelming rescue workers.
"It appears at this time a woman drove into some high water," said Houston Mayor Sylvester Turner at a briefing late Sunday morning, "and drowned while trying to escape." It happened around 9 p.m. CST Saturday in southwest Houston. Turner said the woman was pronounced dead at the scene but an official medical ruling on the cause of death is pending.
The Houston Chronicle reports:
"Just before 11 a.m. Sunday, La Marque police recovered a body from the Walmart parking lot on the Gulf Freeway. The man, a known homeless individual, succumbed to drowning or health conditions, authorities said."
As Harvey hovered over Texas, the National Weather Service tweeted, "This event is unprecedented & all impacts are unknown & beyond anything experienced. Follow orders from officials to ensure safety."
The NWS expected storm totals in isolated areas could reach 50 inches. The AP reported that would be the highest rainfall ever recorded in Texas. As of 6 p.m. Sunday, the storm had dumped more than 24 inches of rain.
In Harris County, where Houston is located, sheriff's spokesman Jason Spencer told the AP that flooding is so widespread that it's "difficult to pinpoint the worst area," as authorities are sifting through calls trying to ensure that life-and-death ones "are at the top of the list."
"We have received more than 2,000 calls for rescues on 911," Turner said Sunday morning. He added that some people have had trouble getting a response but that "it is working" and people should call only with life-threatening emergencies.
At 4:43 a.m. CST Sunday, the city of Houston tweeted, "911 services at capacity. If u can shelter in place do so."
"We have, I would venture to say, thousands of people now who are in a situation where they have taken on water in their homes," Michael Walter, Public Information Officer for Houston's Office of Emergency Management told NPR's Weekend Edition early Sunday afternoon. "We still have reports of individuals who are trapped in their homes and cannot leave. We still have individuals who are seeking refuge on their roofs and in attics."
Emergency management officials requested "that people escaping flood waters as a last resort do not stay in the attic. If the highest floor of your home becomes dangerous ... get on the roof. Call 911 for help and stay on the line until answered."
Chief Art Acevedo of the Houston Police Department asked people to not go into the attic "unless you have an ax or means to break through onto your roof."
Tornadoes have been occurring across Southeast Texas over the past day or so and will continue over the next several days, according to forecasters.
Walter with Houston's Office of Emergency Management said tornado warnings have been "hampering some of our emergency response," making it difficult for helicopters to fly. But he added Coast Guard helicopters that have been aiding recovery efforts are better equipped for the weather than city police helicopters.
More than 3,000 National Guard and State Guard service members are also assisting in recovery efforts, according to Texas Gov. Greg Abbott.
Harris County Judge Ed Emmett said Sunday there was no time to wait for outside assets and called on neighbors to help neighbors. "So those of you who have boats and high water vehicles that can be used in neighborhoods to help move people out of harm's way, we need your help."
Turner, Houston's mayor, said the city's convention center is opening to serve as a shelter. But he asked people not to drive anywhere as area roads remain "impassable."
NPR's Marisa Penaloza reports a Red Cross shelter north of downtown Houston is at capacity with 400 evacuees — some of whom are sleeping on the floor. Penaloza says that some people at the shelter reported there was no food there, but they were able to eat because a Houston police officer paid for McDonald's out of his own pocket.
Gail Delaughter of Houston Public Media spoke to Weekend Edition near I-45, a major north/south route that runs through Houston. "And this section of roadway is depressed underground and is totally flooded right now," Delaughter said. "It's like a river, the water is all the way up to the embankment and you can't even see if there's any vehicles down there right now. Once the water drains out, who knows what they are going to find down there."
Rainfall totaled more than 17 inches in Houston by 9 a.m. CST Sunday.
Mayor Turner warned residents not to be lulled by a pause in the rain. Forecasters Sunday morning projected an additional 15 to 25 inches of rain across the middle and upper Texas coast before the storm is over.
Houston's Metro said it was suspending all bus and rail service. Both Houston Bush Intercontinental and Hobby airports halted flights, likely leading to delays stretching into the week.
Houston TV station, KHOU, has been covering the flooding and evacuations, but was itself overtaken by floodwater. Anchor Blake Matthews tweeted a video of water from a nearby bayou rushing into the downtown studio. He said they continued working from the second floor.
Houston resident David Schulz, 51, was riding his bicycle through shallow water Sunday to check on the church where he works. "I definitely wouldn't get in my car and go anywhere," he tells KERA's Rachel Osier Lindley. "Because I'm noticing that I can be in 6 inches of water and get to a corner and then I'm waist deep ... just like that. So it's very deceiving."
Elsewhere in Texas
Harvey is the most powerful storm to have hit Texas in more than half a century. Even though it had changed into mainly a rain event by Sunday, on Friday night when it slammed into the small coastal city of Rockport, Texas, it was a Category 4 hurricane packing 130 mph winds. A local county judge in Rockport said one person had died as a result of the storm. The judge also said that the number of injured was about 14 people.
NPR's John Burnett reports from Rockport that even though a mandatory evacuation was ordered, around half of the city's residents are thought to have remained.
One resident, Ruben Nino, said he did not have a vehicle and he and his family cowered in their apartment while the storm raged.
"Sheetrock and glass were breaking," Nino said. "We survived in a little closet with four people until we called 911 and they came and rescued us. There was a lot of screaming and praying to Jesus."
In the nearby island community of Port Aransas, officials have been unable to conduct a full assessment of Harvey's toll, because of "massive" damage, reports AP.
"I can tell you I have a very bad feeling and that's about it," Mayor Charles Bujan told AP. Bujan had called for a mandatory evacuation but did not know how many residents heeded the call to leave.
In coastal Galveston County officials made an appeal for owners of "flat bottom" boats to assist with rescue efforts.
But Corpus Christi, just 30 miles south of where Harvey made landfall, appeared to have ridden through the storm largely unscathed Sunday. ABC 13 in Houston said that witnesses in Corpus Christi reported relatively minor damage, including downed trees, but no injuries.
Texas Gov. Greg Abbott said at a press briefing Sunday afternoon that while much focus remains on Houston, "it is important not to forget the challenges that people in the counties outside and around Houston are suffering because of the immense rainfall. That includes, in particular, Liberty County and Brazoria County."
More than 300,000 power outages and 250 highway closures remained across the state, said Abbott.
FEMA Administrator Brock Long told CNN that nearly 5,000 federal workers are in Texas and Louisiana helping restore power, perform search and rescue missions and "pushing forward recovery housing teams ... We're setting up and gearing up for the next couple years." Long added that "this is a storm that the United States has not seen yet."
Mayor Bill de Blasio said New York City is dispatching 120 emergency workers to help with the hurricane response.
Nebraska, Tennessee, Utah, Calif., Missouri, Ohio and Arizona have also provided resources, according to Abbott.
The National Hurricane Center says Harvey is likely to weaken to a tropical depression by Sunday. But continuing rainfall in the days ahead — likely through Thursday — remains the biggest threat. Some areas of Harris County are receiving more than four inches of rain per hour.
President Trump tweeted Sunday, "Great coordination between agencies at all levels of government. Continuing rains and flash floods are being dealt with. Thousands rescued."
Trump held a teleconference with cabinet officials Sunday to go over response and recovery. A White House statement said Trump, "reminded everyone that search and rescue efforts will transition to mass care, restoring power, providing life-sustaining necessities for the population that sheltered in place, and economic recovery."
In another tweet Sunday Trump said, "I will be going to Texas as soon as that trip can be made without causing disruption."
Later, the White House announced Trump will visit Texas on Tuesday.
"We are coordinating logistics with state and local officials, and once details are finalized, we will let you know," Press Secretary Sarah Sanders said. "We continue to keep all of those affected in our thoughts and prayers."
NPR's James Doubek contributed to this report.