By Denise Sternberg, David Goodhue, Douglas Hanks, Rob Wile, Bianca Padró Ocasio, and Martin Vassolo, Miami Herald

Surfside, Florida - The partial remains of the Champlain Tower South condos that partially collapsed, killing an unknown number of residents, have been demolished in a controlled manner late Sunday night (local time) ahead of Tropical Storm Elsa’s impending arrival to Florida.

The instability of the ruins had been dangerous and had hampered the progress of the recovery operation in the section that collapsed eleven days ago.

County authorities didn’t evacuate the Surfside neighborhood that surrounds the remaining structure of Champlain Towers South. Instead, residents between 86th Street and 89th Street from Abbot Avenue and the shoreline were told to remain inside.

"We encourage you to close all of the windows and the doors and all air intakes, and to cover all other openings that may allow dust to enter," Miami-Dade County Mayor Daniella Levine Cava said.

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After the disaster, residents of the part of the building still standing had not been allowed back into their homes for safety reasons, not even to retrieve personal belongings before demolition.

"This is an Independence Day unlike any we have experienced ever before," Mayor Levine Cava commented.

Mayor Levine Cava explained the demolition used a process called "energetic felling" which uses "strategic" explosives designed to bring down the remaining structure using gravity, within the footprint of its existing walls. Residents were advised to stay inside for two hours after the blast to allow the dust to settle.

Kevin Guthrie, head of emergency management for Florida, said beforehand, "Within a matter of minutes... they will be back on the scene [to continue the search for victims]".

As for Tropical Storm Elsa, Mayor Levine Cava said, "we pray for limited impact". The storm is expected to hit the state late Monday night, and though it has already significantly weakened in the interim, it will be packing a lot of rain.

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The apartment complex with around 130 residential units partially collapsed on June 24 for reasons that are still unclear. Since then, the search for buried victims has been virtually round the clock with sniffer dogs, special cameras, and heavy equipment.

The number of dead remains at 24, while 121 remain missing, Mayor Levine Cava announced. On Sunday evening, Miami-Dade police identified David Epstein, 58, as the latest victim in the collapse.