The call went out on Border Patrol radios just before sundown one day this week: 31 immigrants spotted illegally crossing the Rio Grande on a raft.
No sooner had the migrants been found hiding in the mesquite brush than another report came in: A woman and boy were walking up the riverbank.
The Rio Grande Valley has become ground zero for an unprecedented surge in families and unaccompanied children flooding across the Southwest border, creating what the Obama administration is calling a humanitarian crisis as border officials struggle to accommodate new detainees. Largely from Central America, they are now arriving at a rate of more than 35,000 a month.
Anzalduas Park, a 96-acre expanse of close-cropped fields and woodland that sits on the southern bend of the river, has turned from an idyllic family recreation area into a high-traffic zone for illegal migration.
The number of children and teenagers traveling alone from Guatemala, Honduras and El Salvador is expected to reach up to 90,000 across the Southwest border by the end of the year, along with a surge of families with children seeking safe passage into the U.S.
"This is the hottest spot in the nation for crossings," said Hidalgo County Precinct 3 Constable Lazaro "Larry" Gallardo, a valley native who said he had never seen a migration wave of such a scale during his 14 years in office. "Something's got to be done because the numbers are just too high."
Detentions along this stretch of the river have gone from up to 50 immigrants a week to as many as 300. On Tuesday night, constables captured 100, on Monday nearly 200. Authorities are comparing the onslaught of homeless detainees to the displacements brought by Hurricane Katrina.
"The basic difference is that the vast majority of those people were here legally, whereas the current group has come here illegally," said Donald Reay, executive director of the Southwest Border Sheriff's Coalition. "You end up with a double-edged sword. You want to deal with the humanitarian side but also have to deal with the rule-of-law side."
Many of the migrants are young women with children who tell authorities they are fleeing unrest in their homelands. Not long ago, a Honduran woman barely made it across the river before giving birth among the park's red and blue picnic tables and signs warning "Children at Play."
Some migrants cross on weekends and try to blend in with picnicking crowds in the park. But many willingly give themselves up, driven by reports in Central America that immigrants who arrive with children are being allowed to stay in the U.S. indefinitely. (Officials believe smugglers use some families as decoys to divert authorities' attention from other migrants crossing elsewhere.)
One woman walking up the park riverbank this week with a boy made no attempt to flee when Sgt. Dan Broyles, a Hidalgo County deputy constable, approached. She toted two purses, as if headed to the mall — a stark contrast to migrants of years past, who girded themselves with survival gear to endure harsh treks through the desert.
"Did you come on a raft?" Broyles, 51, asked in Spanish.
Yes, the woman said, after traveling by bus from Honduras.
"He's your son?"
Yes, she said, 9 years old. The boy's left arm was in a cast, the result of falling out of a tree before their trip. Around his neck he wore a black-and-white cross woven from plastic lanyards.
"Did you pay someone to cross?"
She said she paid $1,000 — 10 times the going rate before the recent influx.
Her son needs an eye operation she could not afford. She had heard that they would be allowed to stay in the U.S., at least long enough for her to find work and pay for the surgery.
"We can stay temporarily and get money, and if we have to go, we go," she said with tears in her eyes before Border Patrol agents loaded them into a van headed for a station already overcrowded with migrants.
Moments later, a Guatemalan woman walked up to Broyles out of the darkness, with her 15-year-old son and 2-year-old daughter. The boy carried his sister, who wore a frilly green dress and patent leather shoes.
They had been hiding in the marsh, which was filled with tarantulas and lizards. Signs nearby warned of snakes.
Their 15-day journey, she said, had begun after her husband abandoned her, and his brother kicked them out of the family home. Now her jeans, studded with pink rhinestones, were covered in mud and she was crying with relief.
Border facilities in Texas and Arizona have quickly become overloaded. The McAllen Border Patrol station near here, which has space to detain 250 immigrants, instead houses 1,500 daily, according to Border Patrol Agent Chris Cabrera, vice president of the agents' union's local chapter. Other smaller stations in the valley are housing twice or three times their capacity, he said.
Emergency shelters have been opened at military bases in Texas, Oklahoma and California — and at another facility in Arizona — but immigrant advocates and border agents have described the initial intake facilities on the border as badly overcrowded and ill-equipped to handle the onslaught.
Mayeli Hernandez, a 12-year-old Honduran girl who made the trip with her 8-year-old sister, said the journey with smugglers wasn't as difficult as her four days in detention in McAllen last July.
"We were there for four days without showering, without brushing our teeth," Mayeli said. "The guards were always angry. They told me that I was asking for too much water to drink."
In a complaint filed last week with the federal Department of Homeland Security, five immigrant rights groups, including the American Civil Liberties Union Border Litigation Project, alleged that children in custody between the ages of 5 and 17 faced physical and sexual abuse, overcrowding, freezing temperatures, inadequate water and spoiled food.
Their 25-page report documented accounts of sexual abuse, strip searches, a child who had to drink from a toilet tank, filthy restrooms and children forced to sleep on floors.
Border Patrol officials have said they will look into the allegations. Cabrera said agents are also concerned about unsanitary conditions, such as the practice of quarantining sick immigrants behind a piece of yellow tape, strung across the room, that does little to protect agents or fellow migrants.
Cleaning crews wipe the holding areas down regularly, but agents still fear contagious diseases, Cabrera said. "It's not just the disease issues, but the sheer amount of filth that's floating through the air."
President Obama has directed federal agencies to address the widening crisis in the Rio Grande Valley, with new stopgap measures announced almost daily. Yet another temporary detention center is scheduled to open in McAllen, Texas, in a 55,000-square-foot warehouse, Cabrera said.
In Arizona, state officials have rushed provisions, such as vaccines and other medical supplies, to a federal holding facility in Nogales that is being used to hold children who were caught crossing unaccompanied into the Rio Grande Valley.
Immigration and Customs Enforcement officials say they don't have room to detain parents and children long-term.
Children detained by immigration authorities are supposed to be held a maximum of 72 hours, then moved to temporary shelters, where they spend about a month on average before being placed with relatives or sponsors while their immigration cases are pending.
But senior Obama administration officials who briefed reporters this week acknowledged that they haven't been able to meet the 72-hour requirement: There is simply not enough staff to process all the new arrivals.
Once they are processed, the Border Patrol has been flying many families to other states and releasing them en masse at bus stations with notices to appear in immigration courts at their destinations.
At the McAllen Greyhound station this week, volunteers set up tables of donations, then moved to a nearby church hall that was soon overwhelmed by immigrant mothers.
Among them was Blanca Isabel Cruz, 36, who had brought her daughter Xenia, 13, across the river on a raft with smugglers after traveling north by bus from El Salvador. They planned to catch a bus to join relatives in Fredericksburg, Va. The family had migrated in stages: first her 15-year-old daughter with cousins; then her husband, a fisherman, with their 6-year-old daughter; then Cruz with Xenia.
Cruz, a petite woman in a ponytail and a pink T-shirt, said they came because gang violence had worsened in their coastal city of La Union as a 2-year-old truce disintegrated between the country's two largest gangs and a new government failed to help.
"There are gangs and delinquents all over the place," she said. "Here, it's safe."
And the flow continues.
At 11:26 p.m. Wednesday, nearly half an hour after Sgt. Broyles' shift ended, a woman and three boys approached his truck out of the dark.
Belkin Rivera Hernandez, 24, said she'd heard television reports that single mothers would receive permission to stay in the U.S., and decided to try to cross with her son and two other boys from Honduras, hoping to meet her mother in Virginia.
"The situation in Honduras is only getting worse," she said as Broyles handed her a chilled bottle of water, part of a supply deputies buy themselves for the migrants.
Border Patrol agents arrived and loaded the family into a van with half a dozen other women and children.