TERESOPOLIS – The call for help was clearly visible from the helicopter: SOS, carved into the immaculate lawn of an upscale home.
Next to it, people waved and jumped, desperate for help after being stranded for six days by mudslides that obliterated entire communities in the jagged mountains outside Rio de Janeiro, killing at least 700 people as of Tuesday and leaving nearly 14,000 homeless.
"Do we have enough space to land?" the pilot, Col. Orlando Artur da Costa, head of the air rescue sent by Parana state police, asked his crew mates.
Minutes earlier, an attempt to touch down in another isolated area with nearly 330 pounds (150 kilograms) of food, water and medical supplies had been aborted after what at first seemed to be flat dirt turned out to be nearly liquid mud that could have swamped the six-person helicopter.
Three men digging at the edge of the mud flat, their legs protected by trash bags tied around their thighs, were left behind for another mission.
This time Costa got the go-ahead: The space was tight, with sheer drops on three sides, but it was enough. He touched down on the grass and more a dozen women and children crowded around, barely waiting for the rotors to stop.
"We have almost no water left to drink, almost no food," said Adriana Claudia de Melo, 31, gathering up the packages of rice, spaghetti, tomato sauce and bottled water. "We were starting to panic."
Monday's delivery was the first time Melo and nearly 30 other survivors stranded on a hilltop received aid from the government nearly a week after torrential rains unleashed avalanches of rocks and mud in these mountains. Many more families remained isolated by washed-out roads and bridges.
For days after the slides, residents in the most inaccessible areas were forced to fend for themselves, searching for the missing and the dead in the mud and constant rain, and then hiking provisions for hours up and down mountainsides.
Bad weather meant aircraft could not reach more than 20 neighborhoods and villages for days. A break in the rain and improved visibility on Sunday finally allowed 12 helicopters to begin taking supplies and rescue personnel in, and shuttling injured residents out.
Costa's crew started flying Monday. Seen from the air, the scale of the destruction was even more striking: Dozens of crumbled cliffs stood out against the lush green; valleys had turned into muddy rivers; and rivers into silted mud flats, obliterating the communities along their banks.
The city's wealthy often escape Rio's heat to estates nestled in these forested peaks, which are also home to a national park. It was in their employer's stately country house that Melo and the other residents of the cluster of homes called Mariana — caretakers, maids, ranch hands and others — took shelter after their homes were buried or heavily damaged by the slides.
For the five families huddled in the ranch house, the helicopter's arrival staved off desperation.
Diesel fuel for the home's generator was nearing its end, water in the cistern was low and food was being rationed — there were 30 people to feed. There was no phone line to call for help, or to get news of other family members.
Normally, Mariana is a 40-minute drive from Teresopolis, the nearest city. With the five bridges along the route wrecked and the access road washed away, the only way to get to town was a five-hour slog on foot, including several dangerous river crossings.
Larissa Francisco Carvalho, 14, showed off the bruises and cuts on her legs suffered during a trip to town for supplies.
"It's too difficult with the water rushing by, carrying the bags of food," she said. "We needed help."
Maj. Roberto do Canto Wilkoszynski of the Brazilian National Security Force, who is in charge of coordinating the air rescue, said the helicopters started flying as soon as it was safe to do so.
"We can't put the crews in danger," he said. "But we are doing what we can, as fast as we can, and we intend to stay here as long as we need to complete this mission."
And while neighbors helping each other was a valuable lifeline during the first days after the disaster, Do Canto Wilkoszynski said people now need to be careful due to the risk of further landslides, collapsing debris from destroyed homes and contamination from bodies decomposing in the humid heat.
"The ideal is to contact professionals and let them know what's needed," he said.
Back at a helicopter refueling stop in Teresopolis, slide survivor Rejane Melo, 34, sat among packs of bottled water after being airlifted from the remote neighborhood of Santa Rita, where 10 have been found dead.
"You see the state we are in here," she said, motioning to her 6-year-old daughter, Ellen, and her 16-year-old son, Reginaldo, whose leg was amputated below the knee just days before the storms because of cancer. "We couldn't walk out. We were left to God's mercy."
The family were not injured and their home was still standing. But it was left damaged and leaky, and Melo worried it could collapse at any moment in the ongoing rain. There was no water or electricity.
Staying became more unbearable each day, Melo said, as bodies began decaying under the debris, causing an overwhelming stench and raising fears of disease.
Then the helicopter showed up.
"We have to thank God in these moments," Melo said.
After caring for the living, rescuers have to think of the dead. A still unknown number of victims lie under tons of red mud and rock in various valleys.
The first search teams with sniffer dogs arrived Sunday, sent by the National Security Force, which is made up of military troops from various states.
Many gained experience in this kind of work from massive landslides in 2008, but the rough terrain could pose new challenges, team leader Lt. Niccolo Inacio Alves de Sousa said.
How far the bodies were scattered by the rushing floodwaters, and how deep they are buried will determine how many will be found, he said. The search also will be hampered by the lack of heavy equipment, which can't reach many slide sites due to collapsed infrastructure.
How long the house in Mariana will be cut off from town is unclear — rebuilding these rural bridges and roads is not an immediate priority. The five families stranded there fear that once the immediate rescue effort ends, they'll be on their own to face a long recovery.
"We lost our bearings with this," said Carvalho, the teenage girl with the bruised legs. "Now we'll look to each other, and to God, for help."