LAREDO, Texas (AP) - The gentle stream that usually marks the Rio Grande bulged into a mighty river along much of its southern reach Thursday as a rain-packed tropical depression dumped on a Texas-Mexico border region already struggling with flooded homes and evacuations after last week's hurricane.
Authorities in Laredo evacuated several neighborhoods close to the river and a 16-story hotel on the banks as the river grew to 42-feet deep and water began to creep into some homes. The tropical depression-driven rains in Laredo and upstream were expected to keep the water level high for several days, said city spokeswoman Xochitl Mora Garcia.
"It's difficult to describe," said Jerry W. Archer, manager of Rio Grande Plaza Hotel. He estimated the river was about 15 times its usual size. "I was born and raised on the Mississippi River, but people here are used to just a small stream."
The muddy waters - driven by dam releases upstream and rain-swollen tributaries following last week's Hurricane Alex - submerged light poles and towering palm trees, leaving only a few fronds waving above the water line.
National Guard troops arrived Thursday to help with evacuations, and people in low-lying areas gathered sandbags to protect their homes before being forced to leave. But no major injuries had been reported in Laredo.
Nancy Castillo, 35, picked up sandbags while her sister prepared to evacuate from her home near a dry creek bed overflowing with water that normally would head into the Rio Grande.
"It's typically dry everywhere in Laredo - except now," she said.
Tens of thousands of people already had been 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 Alex.
Humberto Moreira, governor of the border state of Coahuila, said more than 20,000 homes had been flooded in his state alone, and about 80,000 people had "lost all of their furniture." A similar number of people had their homes damaged in Nuevo Leon, said that state's Gov. Rodrigo Medina.
Access to the Coahuila city of Sabinas was largely blocked Thursday after several bridges on two main highways collapsed when the Rio Sabinas overflowed, said state interior minister Armando Luna.
"This has made it difficult to get help to the area," Luna said.
Gov. Eugenio Hernandez of the border state of Tamaulipas reported the first fatality there; telling an emergency evaluation meeting attended by President Felipe Calderon in the border city of Matamoros that the victim tried to cross a flooded road.
The tropical depression made landfall at South Padre Island late Thursday morning and was expected to dump four to eight inches of rain across the area, with as much as 10 inches in some parts, said the National Weather Service. That rain comes on top of the five to seven inches Alex already had deposited.
The rain, saturated ground, swollen rivers and releases from dams upstream have experts watching the Rio Grande closely.
In Laredo, where roughly half of all U.S.-Mexico trade crosses, authorities closed two bridges and severely limited traffic on a third. They also restricted traffic on the World Trade International Bridge to keep the weight load on the bridge at a minimum, but they did not have to close the connection.
The World Trade bridge carries roughly 8,000 18-wheelers a day, and closing it would have crippled the nation's busiest inland port.
City officials planned to reopen one bridge on the far northwestern edge of the city Friday morning.
But officials continued to worry about a half-dozen tractor trailers bobbing down river near downtown after being left too close to the rising water, said City Manager Carlos Villarreal.
"It's like a missile headed for a target," he said of the trailers' potential to damage the bridge structures.
Downstream in Rio Grande City, water from dam releases and the tropical depression were converging to create a serious flood threat.
The National Weather Service issued a flood warning for the area after the river more than doubled its normal size. Flooding would damage farmland and could push water from a creek along the eastern side of town into neighborhoods.
At the Retama Manor nursing home in Rio Grande City, administrators waited for local emergency officials to advise them of any risk posed by the Rio Grande. The facility sits next to the international bridge on the banks of the river, just feet from the swift-moving river.
Facility spokeswoman Nan Impink said there is a plan 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.
Farther south, part of the Rio Grande flow was being diverted into miles of wide channels that will eventually send some of the flow to the Gulf of Mexico. The International Boundary and Water Commission said the last similar diversion happened after 1988's Hurricane Gilbert.
Crews broke a 200-meter hole in the pavement of a highway linking Reynosa and Matamoros to allow water to flow through a long-dormant channel, said Pedro Garza, who heads the water commission's Rio Bravo Basin agency.
Garza said he was confident the combination of U.S. and Mexican emergency channels would siphon off enough water to avert the threat to Matamoros downstream. But some questioned why dam levels along the river and its tributaries were kept so high before the rains hit.
"The problem is, we had rainfall beyond historic levels," Garza said.
The IBWC has had to release water from the binational Amistad Dam at its fastest rate in a quarter century after the reservoir reached its highest level since 1974. Water also was being released at Falcon Dam downstream Thursday.