The 9-year-old French boy who's father and mother succumbed to the extreme temperatures at White Sands National Monument was reunited with his grandmother in Albuquerque Thursday evening, Otero County Sheriff Benny House said. 
 
 "The grandmother flew into Albuquerque from France," House said. "Children, Youth and Families Department transported the boy to meet up with the grandmother and release him to his grandmother Thursday afternoon. He was in the care and custody of CYFD." 
 
 He said the state Office of the Medical Investigator's preliminary autopsy report indicates the couple died from heat related illness. 
 
 "The OMI had the couple transported up to Albuquerque for an autopsy," House said. "We have not gotten an official report back as of Friday. We did get a verbal report back from OMI. The preliminary indication is heat related illness." 
 
 The monument had an autistic El Paso boy reported missing in January 2012 while visiting with his family, but rescuers were able to locate him the next day. 
 
 Erica Hoekstra, 23, of Sheldon, Iowa, died while hiking at the monument but prior to that a Japanese businesses man visiting the area died while hiking at White Sands in 2009. 
 
 He said Otero County Sheriff's Office investigators learned through investigation that the couple had two 20 ounce bottles of water with them during their hike Tuesday. 
 
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 "They didn't have any water when we found them," House said. "They had the two empty 20 ounce bottles with them. They learned from the child that the water bottles were full when they left on their walk. The father and mother would take one drink while they made the child take two swallows of water. It might have been why the child fared so well due to his smaller stature, plus he probably consumed more water than they did. They only had 40 ounces of water between them because when we found them they didn't have any water on them." 
 
 The two French tourists David Raoul Steiner, 42, and Ornella Del Guidice Steiner, 51, died while hiking the five mile Alkali Flat Trail loop at White Sands National Monument Tuesday afternoon after park rangers on a routine patrol found the mother, Ornella, then the father, David, about 1.5 miles from the trailhead. 
 
 House said David and Ornella are both from Bourgogne, Reims, France, which is about 100 miles east of Paris. Their son was found alive next to his deceased father, David. 
 
 He said the couple's son was transported to Gerald Champion Regional Medical Center and treated for dehydration. 
 
 The three individuals were traveling across the United States, visiting national parks and monuments, House said. 
 
 He said park rangers discovered the three nationals while on routine trail patrol on the Alkali Flat trail around 5:15 p.m. 
 
 House said Otero County Sheriff's deputies and medical personnel were called to White Sands National Monument for assistance. 
 
 Upon arrival deputies learned Ornella was found unresponsive by park rangers doing a routine patrol, he said. 
 
 House said deputies and rangers began to review items in the area believed to belong to Ornella then information learned led them to David and the couple's son. 
 
 David was found unresponsive but their son was alive and later received medical treatment at the scene and transported to Gerald Champion, he said. 
 
 House said deputies and rangers were able to find David and the couple's son by following tracks which led them to the father and boy. 
 
 "They need to take plenty of water," he said. "Hydration is important in these high temperatures. They have a sign-in sheet at the entrance to the trail. They did not sign in. It was a sheer accident that they were found. The park service was out doing their job and came across them. It looks like they started out about 1 p.m. and started getting into trouble around 3:30 p.m. and around 5:17 p.m. is when we got the call." 
 
 He said the investigation revealed Ornella, David and their son arrived at the monument between 11:30 a.m. and 12:30 p.m. and began to walk the trail before 1 p.m. when temperatures were between 100 and 101 degrees. 
 
 During their hike, Ornella began to slow, but directed David and their son to continue on the trail, House said. 
 
 He said deputies and rangers learned through investigation that David began to slowdown and appeared disoriented. 
 
 The couple's son told investigators that David collapsed, but the boy stayed with his father until the boy was located by deputies and rangers, House said. 
 
 He said both adults were pronounced dead at White Sands National Monument by a field deputy from the Office of the Medical Investigator at the scene. ||||| (CNN) The sun and heat are harsh in the summer, and shade is nowhere to be found. But from all over, people come to admire the otherworldly beauty of the wave-like white dunes and to hike a trail marked only by posts staked deep in the gypsum sand. 
 
 Hikers at the White Sands National Monument in New Mexico are warned about the desert conditions and advised to take many precautions. In the summer, those include drinking lots of water -- a gallon a day is recommended -- and resting frequently. Temperatures often top 100 degrees. 
 
 That heat claimed the lives of a French couple hiking the undulating dunes of the Alkali Flat Trail with their 9-year-old son. The mother and father were both overcome by the temperature and died of heat-related illness, collapsing at different points along the trail, the local sheriff said. 
 
 The mother turned back when she didn't feel well and died on her way to the car. Unaware she had collapsed, the father and son continued on -- but the man, too, became disoriented and then died with the boy at his side, Otero County Sheriff Benny House said. 
 
 Though dehydrated, the boy survived. But he might not have made it were it not for a sheriff's deputy who was first called to help the child's mother. 
 
 The clue on a camera 
 
 Two park service employees on patrol Tuesday discovered the mother first, according to Marie Sauter, superintendent of the White Sands National Monument. 
 
 They called the Otero County Sheriff's Office, which sent deputies and emergency responders, but 51-year-old Ornella Steiner already was dead. 
 
 "They were trying to figure out why she was on the trail by herself," Sheriff Benny House told CNN. 
 
 Looking at Steiner's camera for clues, the deputy saw photos of a man and boy at the park's entrance. They were unaccounted for, House said, so deputies then extended their search. 
 
 Deputies found the father and son about 45 minutes later, slightly off the trail. David Steiner, 42, was dead. The son, whose name was not given, was with him. 
 
 "He wasn't crying," House said, but "he was dehydrated and of course he was upset." 
 
 Overcome by the heat 
 
 The boy was taken to a hospital and French consular officials were notified, House said. But the boy didn't speak English, so in the meantime the sheriff's office found an interpreter -- the mother of a deputy's girlfriend, who is fluent in French. 
 
 From what the boy told investigators, the sheriff said, the family got about a mile and a half down the 4.6-mile-loop trail when the mother, who already wasn't feeling well, tumbled and aggravated a previous knee injury. 
 
 She headed back to the trailhead but made it only about 300 feet before collapsing. 
 
 The son and father continued walking for another 2,000 feet, unaware of the mother's collapse, but the father grew delirious and "started to make some bad decisions for the child," the sheriff said. 
 
 "He kept telling the son that the vehicle is 'right over here, right over here,'" House said. He was disoriented, and "the heat was affecting his judgment." 
 
 An autopsy on the parents isn't back yet, House said, but the medical examiner says their deaths appear heat-related. 
 
 Harsh environment 
 
 Alkali Flat Trail takes visitors through the scenic white sand dunes to the edge of the Alkali Flat, a lakebed that dried up thousands of years ago, after the last ice age. There is no shade among the dunes, the highest of which rises about 60 feet, and sparse short shrubs are the only vegetation. 
 
 It's not the most heavily used trail at the park because it's strenuous and long, going up and down for 2.5 miles before it loops back around, Sauter said. 
 
 "It's a trail that you want to take half a day to do," she said. 
 
 The trail's path isn't visible in the sand. Instead, the way is marked by white posts with orange reflective tape, planted 3-to-4-feet deep in the sand and set varying distances apart but intended to be visible from post to post. Hikers walk from one trailpost to the next. 
 
 With the blowing wind and sand, park employees frequently have to check that the markers haven't fallen down. Visitors are told to turn back if ever they can't see the next one. 
 
 On the day the Steiners died, the high temperature was 101 degrees under sunny skies, Sauter said. 
 
 "It was a typical summer day. We hit the low 100s throughout the summer almost every day," she said. 
 
 Once hikers get into the dunes, she said, "there is no shade. There is no cover. You are out exposed to the sun, the wind, the heat, the reflection of the sun off the white sand. It's a harsh desert environment." 
 
 On the White Sands National Monument website, the Park Service warns visitors that heat-related illness is common in warm weather and can be fatal. It advises people to hike during cool times. 
 
 "Carry food and at least two quarts of water," it says. "Rest, eat and drink when tired. Drinking water is available only at the Visitor Center. The white sand reflects sunlight. Protect all exposed skin from sunburn. Protect your eyes by wearing sunglasses. We recommend that you do not hike alone." 
 
 The Steiners' deaths were the third and fourth at the park in the past 10 years, the sheriff's office told CNN affiliate KVIA 
 
 'It's just a tragedy' 
 
 Sauter said the park offers its condolences and sympathies to the Steiners' family and community in France. 
 
 "They're on our minds," she said. 
 
 "None of us want to ever see an incident like this, so we just try to arm the visitors as best as possible so they can make good decisions for themselves and their families for their visit," she added. 
 
 The boy's grandmother arrived in Albuquerque from France on Thursday and employees from social services took the boy to be with her, the sheriff said. 
 
 "It's just a tragedy," House said. 
 
 "It was the perfect storm for this family. They started off the trek with two 20-ounce bottles of water. When we got there, there was no water left in the bottles." 
 
 He added, "I just think they weren't prepared for that type of heat. I just think they underestimated the desert." ||||| Enzo Steiner, nine, tells rescuers that parents Ornella and David took one mouthful of water while making him take two during fatal hike in New Mexico 
 
 It was supposed to be a dream holiday; a five-week road trip around the western United States for travel-mad Ornella and David Steiner, and their son, Enzo. 
 
 The French couple had planned the trip for more than a year and had organised a busy itinerary to see, and photograph, as much as possible. 
 
 
 
 “They’d done a similar trip last year but for only 10 days and kept saying they were going back for longer,” said a friend this weekend. 
 
 
 
 But the trip of a lifetime was to end in tragedy. 
 
 
 
 Last Tuesday, rangers at the White Sands National Monument in New Mexico found the couple dead, apparently from heat and a lack of water. Enzo, nine, was discovered dehydrated and sunburned but alive, next to his father’s body. 
 
 Facebook Twitter Pinterest White Sands National Monument in New Mexico Photograph: Hanout 
 
 Two empty 50cl bottles of water were found with the bodies, well below the 3.8 litres of water the park recommends for each hiker. 
 
 Enzo’s grandmother, who flew out to America after learning of the tragedy, was scheduled to bring him back to France this weekend. 
 
 Park rangers came across Ornella Steiner, 51, first at 17.30 on Tuesday while on a routine patrol of the Alkali Flat trail in the park, a vast desert of bleached sand. 
 
 Looking at the photographs on her camera, they realised she had been hiking with a man and a child. Driving further into the park, they came across her husband, 42, and son a couple of miles further on. 
 
 Enzo told rescuers his mother had decided to return to their hire car after feeling unwell in the heat that hovered above 38C. When his father became unconscious, Enzo, not knowing what else to do, decided to stay with him. 
 
 
 
 Rescuers said it appeared that the parents, who had not signed the park’s entry register, had left for their hike shortly after midday when temperatures can reach 40C. Park officials advise early morning or late evening hikes. They added that Enzo told rangers his parents had given the best part of their dwindling water supply to him. 
 
 
 
 Benny House, the local sheriff, said the boy had told them that his mother and father had “taken one mouthful, while they made him take two”. 
 
 
 
 “Perhaps that’s why he came out of it alive, because he is smaller and probably drank more water than them,” House told the local Alamogordo Daily News. 
 
 
 
 Facebook Twitter Pinterest White Sands National Monument - The park authorities warn visitors against underestimating the heat and risk of dehydration. Photograph: Alamy 
 
 “They underestimated the elements,” a county official told Agence France-Presse. 
 
 David Steiner’s father, Alain, told Le Parisien his son, who ran a press and advertising agency in Burgundy where the family lived, was passionate about travelling and had been planning his US trip for more than a year. 
 
 He admitted he had expressed reservations that his son was trying to pack too much into the visit, but said: “Children often don’t listen to their parents. This was fatal. 
 
 
 
 “On Wednesday morning, the police rang at my door … they gave me a letter from the Foreign Affairs ministry telling of the death of my son and daughter-in-law. Of course, I cried like a child even though I’m 69 years old.” 
 
 He added: “According to the ministry’s information, David and Ornella gave all their water reserves to their son to allow him to survive. But the circumstances of their deaths aren’t yet known. 
 
 
 
 “My wife and travelled a lot with David when he was young. We visited at least 20 countries and gave him the bug. He travelled a lot with Ornella and was passionate about photography.” 
 
 
 
 He said his grandson had not spoken about his parents. “I told him you’re coming back to nanny and granddad, who can’t wait to see you.” 
 
 Ornella Steiner worked for more than 20 years at the Reims town hall where colleagues were said to be deeply shocked. 
 
 
 
 White Sands National Monument is one of the world’s great natural wonders with enormous wave-like dunes across 275 sq miles. The park authorities warn visitors against underestimating the heat and risk of dehydration. 
 
 Postmortems are being carried out to determine the exact cause of the Steiners’ deaths. 
 

– Tragedy at White Sands: A French couple who disastrously underestimated the power of the New Mexico desert died in the heat but used what little water they had to keep their son alive, the Guardian reports. From what investigators can piece together, Ornella and David Steiner and their 9-year-old son, Enzo, set out to walk a 4.6-mile-loop trail at the White Sands National Monument on Tuesday but only took two 20-ounce bottles of water among them when authorities recommend a gallon each, CNN reports. The park recommends hiking during cooler hours, but the family set off at around 1pm on a day when temperatures topped 100F and failed to sign in at the entrance to the trail, which goes up and down through sand dunes and offers no shade whatsoever. The county sheriff tells the Alamogordo Daily News that Ornella turned back first after slowing down but told the other two to continue. She died of heat-related illness on the way back to the car, and David also collapsed some 2,000 feet later and died after becoming disoriented, the sheriff says. He notes the boy, who was found alive next to his father's body, told police his "father and mother would take one drink while they made the child take two swallows of water." The sheriff tells CNN that park employees on a routine patrol found Ornella's body first, then searched for the father and son after looking through her camera for clues and seeing a photo of the two at the park entrance. Enzo was treated for dehydration and his grandmother has flown out from France to bring him home, the Daily News reports. (A Yellowstone hiker whose body was found Friday was likely mauled to death by a grizzly.)