As a strong storm dumped rain on the already high Rio Grande, those living downstream braced for a torrent of water that has led to the closure of two international bridges and evacuations on both sides of the U.S.-Mexico border further up the river.
Residents of some neighborhoods in the downstream towns of Roma and La Grulla were being evacuated in anticipation of floodwaters. Shelters were readied for residents of low-lying neighborhoods in several communities. And the last hand-drawn ferry on the U.S.-Mexico border was hauled out of the Rio Grande's swift and rising waters for the second time this week.
A tropical depression that came ashore just north of the mouth of the Rio Grande on Thursday was expected to add 6 inches to 8 inches of rain to rivers and reservoirs in south Texas and northern Mexico already swollen from the heavy rains dropped by Hurricane Alex last week.
In Rio Grande City in Starr County, the river reached 52½ feet, just over flood stage early Friday. A flash flood warning was scheduled to remain in effect for the lower Rio Grande Valley until Friday night.
Starr County Emergency Operations Director Gene Falcon said flooding from the river likely would effect farmland in the area, but the larger problem would be what the river did to a local tributary, the Arroyo Los Olmos along the east side of town.
"The river level will be so high that it will start backing up (the creek)," Falcon said.
It already was starting to happen late Thursday as water in the creek appeared stagnant and possibly even moving slightly upstream, away from the Rio Grande. Some residents in neighborhoods along the scrub-choked creek were beginning to move valuables to higher ground.
At the Retama Manor nursing home, administrators waited for local emergency officials to advise them of any risk posed by the Rio Grande. The facility sits next to an international bridge on the banks of the river, just feet from the swift-moving water.
Nan Impink, a spokeswoman for the facility, said a plan is in place to move residents if there is a danger of flooding.
"For us that's an option of last choice because it's very disruptive to patients," she said.
The International Boundary and Water Commission, which operates dams, reservoirs and levees along the Rio Grande, increased the amount of water released from Falcon Dam, just west of Roma, on Thursday, while also diverting part of the river's flow into a wide floodway near Mission.
Roma's police chief, Jose Garcia, said the water was expected to rise 4 feet to 6 feet overnight, prompting the decision to require about 30 families to evacuate from small subdivisions near the river.
"We just want to make sure we don't get caught by surprise," Garcia said.
Even as the remains of the tropical depression moved west through northern Mexico, heavy rains were forecast for south Texas, said meteorologist Joseph Tomaselli of the National Weather Service in Brownsville.
"We won't begin to dry out until Saturday," he said.
In Los Ebanos, home to the only hand-pulled ferry on a U.S. international border, ferry operator Mark Alvarez was directing Sullivan City firefighters as they attached tow lines and began dragging the ferry toward dry land. Just across the fast-moving river in Mexico, teenagers dove head first into the river from the roof of a submerged building along the water's edge.
"We want to pull it up because we don't want the current to take it," Alvarez said. "We're going to dry dock it as much as possible."
Upstream, authorities in Laredo evacuated several neighborhoods close to the river and a 16-story hotel on the banks Thursday as the river grew to 42-feet deep and water began to creep into some homes. Officials had no tally of flooded homes, but up to 2 feet of water flooded at least a few streets.
The river crested in downtown Laredo overnight but was expected to remain high for the next several days, forcing evacuated residents to stay out and limiting traffic on the city's international bridges.
Tens of thousands of people were forced from their homes in Mexican towns earlier in the week as dam releases dumped torrents of water into flood-swollen rivers to avoid the risk of out-of-control releases following Hurricane Alex.
Humberto Moreira, the governor of the border state of Coahuila, said that more than 20,000 homes had been flooded in his state alone, and about 80,000 people had "lost all of their furniture."
In Nuevo Laredo, Mexico, dozens of houses in low-lying neighborhoods were flooded late Thursday, with water rising as high as 4 feet in some places. Nuevo Laredo firefighters using ropes, small boats and muscle power managed to lasso about a half-dozen truck cargo containers floating in the Rio Grande, to prevent them from smashing into or damaging bridges.
Access to Sabinas, Mexico in the state of Coahuila was largely blocked Thursday after several bridges on two main highways collapsed after the Rio Sabinas overflowed, said Coahuila state interior minister Armando Luna.
"This has made it difficult to get help to the area," Luna said.
In Laredo, where roughly half of all U.S.-Mexico trade crosses, authorities on Friday reopened one of the international bridges on the northwestern edge of the city, but one downtown bridge remained closed and a second was severely restricted. The vehicle inspection station on the Nuevo Laredo, Mexico, side was under several feet of water.
Traffic was also restricted on the World Trade International Bridge -- a route that moves roughly 8,000 tractor trailers a day between the two countries -- but it remains open.
Michelle Roberts reported from Laredo. Associated Press writers Jorge Vargas in Nuevo Laredo, Mexico; and Oscar Villalba in Piedras Negras, Mexico; Mark Stevenson in Mexico City; and Jeff Carlton in Dallas contributed to this report.