HOUSTON (AP) — Floodwaters kept rising Tuesday across much of Texas as storms dumped almost another foot of rain on the Houston area, stranding hundreds of motorists and inundating the famously congested highways that serve the nation's fourth-largest city.
Meanwhile, the number of people missing in flooding along the Blanco River rose to more than 40, including a group of people who disappeared after a vacation home was swept down the river and slammed into a bridge.
Several more fatalities were reported — two in Houston, another in a vehicle on Interstate 45 and one more in Central Texas. That brought to 16 the number of people killed by the holiday weekend storms in Texas and Oklahoma.
The water continued rising overnight as about 11 more inches of rain fell, much of it in a six-hour period.
Firefighters carried out more than 500 water rescues, most involving stranded motorists. And at least 2,500 vehicles were abandoned on the streets by drivers seeking higher ground, said Rick Flanagan, Houston's emergency management coordinator.
"You cannot candy coat it. It's absolutely massive," Texas Gov. Greg Abbott said after touring the destruction.
The flooding closed several highways in Houston, and the ones that stayed open became a gridlocked mess.
Interstate 45 near downtown was backed up for miles on Tuesday morning, with a handful of motorists traveling the wrong way on the highway to retreat from high water.
The small cars weaved between massive 18-wheelers as drivers stared at them in disbelief. With no end to the backup in sight, some drivers got off the freeway, only to be held up again by water covering nearby access roads.
In the Heights neighborhood about 5 miles from downtown, groups of people roamed the streets after escaping their stalled cars, and police cruisers blocked some roads where the water had caused dangerous conditions.
Some motorists were stuck on Interstate 45 all night, sleeping in their cars until the backup was cleared about 8 a.m.
NBA fans at the Toyota Center, where the Rockets hosted a Western Conference finals game against Golden State on Monday, were asked with about two minutes left in the game not to leave the arena because of the severe weather.
The game ended before 11 p.m., but about 400 people remained in their seats at 1:30 a.m., choosing to stay in the building rather than brave the flooded roads that awaited them outside.
A spokeswoman for the flood district of Harris County, which includes Houston, said up to 700 homes sustained some level of damage.
In Hays County, about 35 miles southwest of Austin, Commissioner Will Conley said authorities were looking for 42 people, including a dozen people who witnesses said they saw in the floodwaters.
The rest may be unaccounted for simply because they are staying elsewhere or are not at home, Conley said.
Crews were also searching for victims and assessing damage just across the Texas-Mexico border in Ciudad Acuna, where a tornado killed 13 people Monday.
Some of the worst flooding damage in Texas was in Wimberley, a popular tourist town along the Blanco in the corridor between Austin and San Antonio. That's where the vacation home was swept away.
The "search component" of the mission ended Monday night, meaning no more survivors were expected to be found, said Trey Hatt, a spokesman for the Hays County Emergency Operations Center.
One person who was rescued from the home told workers that the other 12 inside were all connected to two families. Young children were among those believed to be missing.
But by early Tuesday, Hays County spokeswoman Laureen Chernow acknowledged discrepancies concerning exactly how many people were in the home.
"We don't have that certainty," Chernow said.
Eight of the missing were friends and family who had gathered for the holiday, said Kristi Wyatt, a spokeswoman for the City of San Marcos. She said three more were members of another family in a separate situation. An unrelated person was also missing, Wyatt said.
The Blanco crested above 40 feet — more than triple its flood stage of 13 feet. The river swamped Interstate 35 and closed parts of the busy north-south highway. Rescuers used pontoon boats and a helicopter to pull people out.
Hundreds of trees along the Blanco were uprooted or snapped, and they collected in piles of debris up to 20 feet high.
The deaths in Texas included a man whose body was pulled from the Blanco; a 14-year-old who was found with his dog in a storm drain; a high school senior who died Saturday after her car was caught in high water; and a man whose mobile home was destroyed by a reported tornado.
The Oklahoma Department of Emergency Management also reported four fatalities between Saturday and Monday after severe flooding and reports of tornadoes.
In Ciudad Acuna, Mayor Evaristo Perez Rivera said 300 people were treated at local hospitals after the twister, and up to 200 homes had been completely destroyed in the city of 125,000 across from Del Rio, Texas.
Thirteen people were confirmed dead — 10 adults and four infants, including one that was ripped from its mother's arms.
Rescuers were looking for four members of a family who were believed missing.