Miami Condo Collapse Death Toll at 4 as 159 Missing, While Study Claims Structure Sinking Since '90s

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The death toll from the partial collapse of the Champlain Towers South Condo in Surfside, Florida, on has risen to four, Miami-Dade County Mayor Daniella Levine Cava announced in a press conference Friday. 159 people remain unaccounted for as rescue efforts continue.

"Unfortunately, this has been a tragic night. We do have 120 people now accounted for, which is very, very good news. But our unaccounted for number has gone up to 159," Cava said. "In addition, we can tragically report the death count is now four."

The White House also announced that President Joe Biden approved an emergency declaration for Florida, authorizing federal assistance for disaster relief following the Thursday tragedy. During the briefing, Miami-Dade Fire Rescue Chief Ray Jadalla said officials "have hope" for finding survivors within the debris, as they focus rescue efforts on areas they have heard sounds.

"The entire building - the portion that's still standing - was cleared by rescue crews. So at this point now, all resources have been shifted to the rubble, including from above and from below," he said. "Every time that we hear a sound, we concentrate on that area."

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As the search for survivors continues, the cause of the collapse remains unknown. During the press conference, the Miami-Dade Police Department confirmed an investigation is ongoing.

Meanwhile, a professor at Florida International University has come forward to claim that the building, constructed in 1981, has been sinking since the 1990s.

Shimon Wdowinski, a professor in the Department of Earth and Environment at the college, said his 2020 study of the site "detected" the collapse of the 12-story high-rise, USA Today reported. Wdowinski said the study indicated the building was sinking 2 millimeters a year in the 1990s, noting, however, there was rate could have slowed or accelerated in the years since.

"I looked at it this morning and said, 'Oh my god.' We did detect that," he told the outlet. "It was a byproduct of analyzing the data. We saw this building had some kind of unusual movement."

Champlain Towers South was undergoing a standard recertification process, involving electrical and structural inspections, at the time of the tragedy. The process had not yet been completed.

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Nevertheless, Wdowinski and Florida authorities say it's too soon to draw conclusions on the cause of the collapse.

"We will continue search and rescue, because we still have hope we will find people alive," Mayor Levine Cava stressed during Friday's press conference.

This story is developing. Check back for updates.