Summer thunderstorms in the Miami area made it difficult to search the debris of Champlain Towers South. This hindered crews who used sonar, sniffing dogs, and special machinery.
Family members of the missing were waiting in desperate wait at the Surfside community center, on Florida's Atlantic Coast, as the condo building of 12 stories came crashing down.
"This has been a remarkable day and a quarter," Daniella Levine Cava said at an afternoon press conference.
"Our hearts are with first responders who went in desperate search of people, were motivated to find them, and hopeful that they would find them. We are proud of them.
"And to all the families that are in pain, waiting, wondering, or needing news about their loved ones, we are here for you."
Crews worked 15-minute shifts throughout the night. They were delayed by thunderstorms, and had to work in shifts until the morning.
Officials announced Friday morning that the death toll had risen to four, and warned that it would continue to rise. Stacie Fang was the first victim to be identified. Her 15-year old son was pulled from the debris on Thursday.
Joe Biden signed an emergency declaration in the region on Friday morning. Federal funding was now available. The White House sent condolences.
At an event to sign a bill naming a national monument at the site of another Florida tragedy, the 2016 Pulse nightclub massacre, the president stated, "It's tough, tough times."
"There are so many people still waiting. Is it possible they are still alive? If so, when will they be and what will happen? Our hearts go out to them.
"I promise that the Congress and the Administration will do everything they can to assist you now and after this happens, after they determine exactly what the state is."