TUCSON, Ariz. -- A record 460 illegal migrants died crossing the U.S.-Mexico border in the past year, a toll pushed higher by unusually hot temperatures and a shift of illegal migration routes through the remote desert.
The death total from Oct. 1 through Sept. 29 surpassed the previous record of 383 deaths set in 2000, according to statistics compiled by the U.S. Border Patrol.
The dead were mostly Mexicans, many from the states of Mexico, Guanajuato and Veracruz, but also from the impoverished southern states of Oaxaca and Chiapas.
Migrants continue to die in automobile accidents and from drownings while crossing roads and waterways into California and Texas, but 261, or more than half the total, perished while crossing the Arizona deserts, the busiest illegal immigrant corridor along the nation's 2,000-mile border with Mexico.
The migrants, herded across the border by smugglers, have been traversing increasingly desolate stretches of desert as the Border Patrol cuts off more accessible routes.
Arizona's most dangerous crossing is a 45-mile corridor between Sasabe, Mexico, and Three Points, Ariz., where the bodies of more than 40 people were found in the washes and sand since the beginning of the Border Patrol's fiscal year.
"It's overwhelming," said Dr. Bruce Parks, the chief medical examiner for Pima County. Outside Parks' office, a refrigerated tractor-trailer holds 60 bodies, mostly dead migrants, an overflow from the morgue. "This is an emergency for us."
The death toll, largely the result of heat-related illnesses, was driven higher by more than 30 straight days of 100-degree-plus temperatures in parts of Arizona, according to the Border Patrol. The figures also reflect better record-keeping by the agency, which checks regularly with coroners' offices to include bodies found by other agencies.
Border Patrol officials also blame the increase on smugglers who lead migrants into dangerous terrain without sufficient food or water. Facing stiffer enforcement, they are more likely to abandon migrants at the first sign of trouble, agents say.
"It's the Sonoran Desert, miles and miles long ... and absolutely no infrastructure - roads, telephone or houses - with very little shade," said Mario Villarreal, a Border Patrol spokesman.
Immigrants rights activists say the record death total is a product of the U.S. border enforcement strategy that forces migrants to take ever more isolated routes.
Activists at a memorial in Tijuana this weekend read off more than half of the names of the 3,600 migrants who have died since U.S. authorities beefed up enforcement in California 11 years ago, according to Mexican statistics. The crackdown, called Operation Gatekeeper, pushed migration routes east to the remote stretches of deserts in Arizona.
In recent years, the number of Border Patrol agents in Arizona has increased a third, to 2,850, and the border has been fortified with extra lighting, fencing and sensors. The agency doubled the number of aircraft patrolling the border this year, including helicopters and unmanned drones.
Helicopters that hover over open desert areas, some agents and observers say, have driven migrants into a mesquite-covered expanse along state Route 286 that offers migrants cover from aerial sightings but is miles from the nearest town.
Special Border Patrol search units in the Tucson sector have rescued 850 migrants, 300 more than last year, according to the Border Patrol. But critics say the agency shouldn't receive credit for a strategy that inevitably creates more perilous passages.
Some of the migrants who died came from the economically depressed states of Oaxaca and Chiapas, a region that in recent years has become a major exporter of migrants to the United States.
Experts say people from those states are more vulnerable than other migrants because they are often indigenous people who don't speak Spanish and lack the connections to more widely used smuggling networks.
Richard Marosi writes for the Los Angeles Times.