The likely trigger or triggers of the Champlain Towers South collapse may not be known for months. But NBC 6 Investigators found clues to how it happened may be gleaned from the final minutes the building stood and what was left behind.
Watching the surveillance video of the collapse, you might think it lasted around 15 seconds. But a review of 911 calls and witness interviews revealed a longer process - lasting more than six minutes.
After a loud bang announced something was wrong, a 911 call came in on June 24 at 1:16 a.m. “It’s a big explosion. Come at 8777,” the caller said, referring to 8777 Collins Avenue.
Another call came in 12 seconds later “...We’re calling in a fire alarm for a business.”
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There’s no evidence at this point of a fire or explosion prior to collapse. But Gabriel Nir, a survivor who lived on the first floor of the building just above the underground garage told NBC 6 he heard and felt what he called “the first collapse.”
“The first collapse happened. Me and my mom, my sister went out first collapse,” Nir said. “We see the collapse happening on the pool side and I saw a bunch of cars like going in, inside the car garage,” Nir said.
Drone video shows the cars which dropped from first-floor parking spots near the condo entrance into the underground garage.
Alerted by the noise while swimming outside the adjacent Solara Surfside Resort, Adriana Sarmiento began recording a cellphone video at 1:18 a.m.
The video, provided to NBC 6, aimed down the garage entrance ramp off 88th street. It shows water flowing and what appears to be broken concrete, lying on the garage floor beneath Nir’s unit.
Nir told NBC 6 he sensed a second collapse shortly after.
“At that moment, I saw the ground shaking. I felt like something was happening,” he said. “I told my mom, my sister, everyone starts running.”
By the time Nir called 911 at 1:19 a.m. - he had less than three minutes to escape.
Another 911 call captured the exact moment units began tumbling onto Nir’s unit and garage below. That call was at 1:22 a.m. just under six minutes from the first 911 call to the loss of dozens of lives in a crush of concrete and steel.
That delay is no surprise to Allyn Kilsheimer, the engineer the town of Surfside hired to figure out what happened.
“When buildings talk to you, you have to listen to them,” Kilsheimer told NBC 6.
When asked what the Champlain Towers South was saying on June 24, he responded “It’s got a big problem.”
Kilsheimer saw it at the Pentagon on Sept. 11, 2001.
“The fifth floor stayed there for 15 minutes,” Kilsheimer said. “Then … it said, I gave up.”
Kilsheimer told NBC 6 he believes that’s what happened at Champlain Towers South, based on the information he knows at this point. The oceanfront units at the building stood swaying for seven seconds before forces inevitably brought them down.
As for the root cause?
Kilsheimer is barred from the site, while the National Institute of Standards and Technology (NIST), a federal laboratory, conducts its investigation.
“I would love to be able to do some materials testing ... I would love to do the foundation testing we want to do in the South but we can’t do those yet because Miami-Dade Police consider it a crime scene and it is all evidence,” Kilsheimer told NBC 6.
One point of interest: columns and beams at the bottom of the ramp leading into the garage.
Photos taken this week, just east of the area, show a large beam structure that appears to have fallen into the garage floor.
When and how that happened is not known. But it lies in an area of great concern. It’s the same area where it appears the first part of the building above ground began crumbling into dust.