By Francisco Alvarado
SURFSIDE, Fla. (Reuters) -Some 159 people remained unaccounted for on Friday after the collapse of a residential building near Miami left families clinging to hope as search-and-rescue teams combed through a mountain of debris looking for any signs of life.
The official death toll from Thursday's disaster stood at four and was certain to rise as rescuers battled smoke, fires and the precarious state of the rubble while working in the south Florida heat.
Although the outlook appeared grim, with one floor of the high-rise stacked on another like pancakes, rescuers continued to search the debris in the hopes that pockets had formed, leaving any possible survivors air to breathe.
"We have hope because that's what our search-and-rescue team tells us, that they have hope," Miami-Dade County Mayor Daniella Levine Cava told a news conference.
But the number of people unaccounted for remained constant throughout the day, meaning rescuers had not found any bodies or survivors.
Aided by dogs, cameras and sonar, the teams worked the site on a rotation, with a limited number allowed at any one time to prevent further collapse, Levine Cava said.
Teams from Mexico and Israel arrived to help relieve the locally based crews, many of whom have also traveled to disaster sites around the world.
Atop the pile, some wielded hammers and picks looking for signs of life. Heavy equipment scraped away the top layer.
Below ground, rescuers who entered through the parking garage risked their own lives searching for survivors, occasionally being hit by falling debris, officials said.
Miami-Dade Fire Rescue chief Andy Alvarez recalled that his team once pulled a girl out of earthquake debris in Haiti eight days into the rescue effort.
"You gotta have hope. We're doing everything we can to bring your family member out alive," Alvarez told the loved ones of the missing on CNN, pausing as he was overcome with emotion.
The disaster occurred early on Thursday morning, when many people would have been asleep, as a large section of the 40-year-old high-rise crumbled to the ground https://graphics.reuters.com/MIAMI-BUILDING/nmovaxnykpa/miami-building-satellite.jpg.
Video captured by a security camera showed an entire side of the building suddenly folding in two sections, one after the other, at about 1:30 a.m. (0530 GMT), throwing up clouds of dust.
The Champlain Towers South condominium is in Surfside https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftmsnrt.rs%2F3h5inB4&data=04%7C01%7CJonathan.Oatis%40thomsonreuters.com%7C16d12151a9564c1aae7008d937ddc0e9%7C62ccb8646a1a4b5d8e1c397dec1a8258%7C0%7C0%7C637602247849391470%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ZHbU0p1t6YR4AG%2FwkdvDSyFnM9EmAloM9ET%2FaN3sc5g%3D&reserved=0, a barrier island town across Biscayne Bay from Miami.
Dozens of people were gathered at a reunification site at the Surfside Community Center - a hectic scene with volunteers running around and people hugging to console one another.
Survivor Janette Aguero, her husband and her two teenage children had been staying in her mother-in-law's apartment for vacation this week. Around 1:20 a.m. on Thursday, she was startled by what felt like an earthquake, she said. Her family ran down the stairwell to escape.
"A million things raced through my mind," Aguero said. "I grabbed the kids and our phones. That was the only thing we could take because everyone was telling us we had to get out."
"The room where my children slept is only 15 feet away from the section that collapsed," she said.
The 12-story building had more than 130 units, about 80 of which were occupied, officials said. Roughly half appear to have collapsed.
Rescuers had heard sounds in the rubble overnight, which could have been falling debris or people tapping, Miami-Dade Fire Rescue chief of operations Ray Jadallah said.
Officials did not report hearing more of those sounds during the day, however.U.S. President Joe Biden approved an emergency declaration in the state of Florida and ordered federal assistance to supplement state and local response efforts, sending Federal Emergency Management Agency officials to the scene.
"Our hearts go out to them," Biden said.
The cause of the collapse remained a mystery.
Satellite data from the 1990s showed the building was sinking about 1mm to 3mm per year while surrounding buildings remained stable, said Florida International University professor Shimon Wdowinski.
"Either the building is settling into the soil or maybe there is some compromise with the structure, a compromise within the building. We cannot really say," he said in a telephone interview.
There was insufficient data to show whether the movement continued since then, Wdowinski said.
Officials said the complex, built in 1981, was going through a recertification process requiring repairs.
Surfside Commissioner Charles Kesl told Reuters an email from a building resident in April said the engineering firm Morabito Consultants had been hired to do the building's recertification. The recertification application, due this year, had not yet been formally submitted, Kesl said.
Kesl said the email, which he declined to share, mentioned the condominium was borrowing some $15 million for repairs on balcony railings and repairs that were unclear.
"But $15 million isn't crazy extraordinary," he said, noting the condominium may have also been using reserves.
Reuters was unable to confirm details in the email. Attempts to reach Morabito Consultants' leadership after hours were unsuccessful.
(Reporting by Francisco Alvarado in Surfside, Florida; Additional reporting by Kanishka Singh in Bengaluru, Rich McKay in Atlanta, Andy Sullivan, Gabriella Borter and Brad Heath in Washington, Alexandra Ulmer in San Francisco, Peter Szekely in New York and Dan Whitcomb in Los Angeles; Writing by Gabriella Borter and Daniel Trotta; Editing by Mike Collett-White, Jonathan Oatis and Sonya Hepinstall)