"Catastrophic" flooding paralyzed Houston and other deluged towns in southeastern Texas early Sunday as Tropical Storm Harvey pummeled and drenched residents and first responders.
More than 1,000 people had been rescued overnight due to record flooding in the sprawling Houston area, according to meteorologist Jeff Lindner with Harris County's Flood Control District.
"Stay put," the National Weather Service advised.
One of two confirmed fatalities in the ferocious storm happened in Houston when a woman drove her vehicle into high water, city police said. Police said they believe the car became inoperable -- or the water was too high to pass through. The victim got out of her vehicle, was overtaken by water and drowned.
A flash flood emergency was in effect for parts of the Houston area. Three to 4 inches of rainfall were reported in the region in one hour's time. The storm spawned tornadoes and lightning, with extensive damage reported.
The National Weather Service said maximum sustained winds Sunday were near 45 mph with higher gusts and some weakening is forecast over the next few days. The tropical storm, forecasters say, in the latest advisory "is likely to become a tropical depression by tonight."
But authorities say now is not the time to relax.
"It's going to last four to five days," Houston Mayor Sylvester Turner said late Saturday. He urged drivers to stay off the road. "This is Day One," he said.
The slow-moving storm is expected to drop 15 to 25 inches of rain over the middle and upper Texas coast through Thursday. There could be isolated storms that reach 40 inches of rain. "Rainfall of this magnitude will cause catastrophic and life-threatening flooding," the weather service said.
Harris County Sheriff Ed Gonzalez said via Twitter that many rescues were taking place overnight in the Houston area and requests were coming in for high-water rescues. "Some involve children, others with medical issues. Trying to get to as many as possible," Gonzalez said.
One rescue involved a hospital transport for a person who had suffered a cardiac arrest. Several people were rescued from a vehicle on a highway.
"Our units are trying to get to everyone as soon as possible," he said.
People are tweeting their locations and asking for help.
One person -- whose mom is diabetic and dad has heart disease -- said, "We need help!! My house is flooded."
Fatality in Rockport
Another fatality was reported in the hard-hit coastal city of Rockport, where a person died in a house fire during the storm, Aransas County Judge Burt Mills said Saturday afternoon. "We didn't know about it until today," he said.
At least a dozen people were injured, Mills said.
With dire warnings of tornadoes, torrential downpours and days of flooding to come, broad swaths of southeast Texas were littered with uprooted trees, toppled signs, flagpoles snapped like toothpicks and clusters of bricks peeled like scabs from walls and rooftops.
Additional fatalities were feared in Rockport, where an estimated 5,000 residents had stayed put for the storm that blasted ashore as a Category 4 around 11 p.m. ET on Friday between Port Aransas and Port O'Connor, Aransas County Sheriff Bill Mills said.
Callers to the local emergency dispatch line told of walls and roofs collapsing on people across the city, where an official had warned those who opted to stick out the storm to write their Social Security numbers on their arms for body identification.
CNN meteorologist and severe weather expert Chad Myers warned residents of Houston to move to higher ground.
"The storm isn't moving, but the rain bands are moving like a pinwheel," he said. "You are going to get a pinwheel (Saturday night) that will wake up -- or you'll wake up with 12-18 inches of new rainfall on the ground."
Shortly after Harvey became a tropical storm, with sustained winds of 70 mph, Saturday afternoon, Gov. Greg Abbott told reporters that the state had more than 1,000 workers involved in search and rescue operations.
"There's been widespread devastation," Rockport Mayor Charles Wax told CNN. He said emergency workers were going house to house to check on residents and assess damage.
"We've already taken a severe blow from the storm, but we're anticipating another one when the flooding comes," he said.
Some places even far inland were predicted to get as much as 40 inches of rain through Wednesday.
While the worst of the storm surge had ended by midday Saturday, the coastal flooding threat was due to increase as already-swollen rivers and bayous get pounded with heavy rain, CNN meteorologist Michael Guy said. Sea water pushed onto the shore also won't recede quickly, he said, meaning "this is going to be a long, ongoing flood event."
Harvey wielded the "highest potential to kill the most amount of people and cause the most amount of damage," Brock Long, director of the Federal Emergency Management Agency, had warned. He echoed forecasters who predicted Harvey would leave areas "uninhabitable for weeks or months," echoing language last seen ahead of Hurricane Katrina in 2005.
Damage assessments underway
Firefighters who hunkered down in their station in Rockport as Harvey passed over the city of about 10,000 residents recounted a harrowing night.
The wind was "howling," said Roy Laird, assistant chief of the city's volunteer fire department. "We had probably 140-mph winds earlier."
For hours, Karl Hattman and his family listened to "what sounded like a freight train" roar outside their Rockport home. When the fury calmed, they headed out into the darkness to find many trees down, debris blocking their driveway and Hattman's vehicle damaged by flying roof tiles.
James Salazar is the captain of the volunteer fire department in Seadrift, Texas.
He rode out the storm and drove around Saturday to check on other residents. Salazar said he had some roof damage at his house, but it was not too bad. He said damage to the town could have been worse.
"As far as homes go, there are some with damage and some that are flooded. It could have been much worse," he said.
Taking shelter and bracing for rain
In San Antonio, about 950 people took refuge in shelters, Woody Woodward, a spokesman for the city fire department, told CNN, adding that there was still plenty of space for more people.
Ten critically ill babies in Corpus Christi were taken to a hospital in North Texas ahead of the storm, the Cook Children's Hospital in Fort Worth said in a statement.
"All our babies made it here safely," Dawn Lindley, a registered nurse with Children's Health Transport Team, told CNN.