[The livestream is slated to begin at 11:30 a.m. ET. Please refresh the page if you do not see the video player above.]The death toll in the collapse of a Florida condominium building rose to 16, with 147 people still unaccounted for, Miami-Dade County Mayor Daniella Levine Cava said at a press conference Wednesday.”Our detectives have been working around the clock to reach every single person who we have been told may be missing,” Levine Cava told reporters.The likelihood of finding more people alive in the wreckage continued to diminish as first responders’ painstaking search-and-rescue efforts enter day 7. No survivors have been pulled from the site since a few hours after nearly half of Champlain Towers South, a 40-year-old, 136-unit condo building, caved in last Thursday.Search and Rescue teams look for possible survivors in the partially collapsed 12-story Champlain Towers South condo building on June 29, 2021 in Surfside, Florida.Chandan Khanna | AFP | Getty ImagesPresident Joe Biden and first lady Jill Biden will travel to the site on Thursday, White House press secretary Jen Psaki said earlier this week.The Bidens plan to personally thank first responders, rescue teams and “everyone who’s been working tirelessly around the clock,” Psaki told reporters Tuesday.In the wake of the collapse, Surfside authorities released a 2018 survey report in which an engineer warned that the building’s waterproofing was causing “major structural damage” and needed to be replaced.”Failure to replace the waterproofing in the near future will cause the extent of the concrete deterioration to expand exponentially,” the report said.That report from Morabito Consultants also found “abundant cracking and spalling” in the concrete columns, beams and walls of the parking garage.A letter from the Champlain Towers South Board President Jean Wodnicki two months before the collapse also warned about the building’s structural issues, pointing to accelerating “concrete deterioration” that had worsened since the initial 2018 report. The specific cause of the cave-in is still unknown.Family members hold vigil for the missing victims of Surfside condo collapse in Surfside, Florida, United States, on June 29, 2021.Tayfun Coskun | Anadolu Agency | Getty ImagesLevine Cava on Saturday also announced a full investigation, and said she would direct the Department of Regulatory and Economic Resources to immediately start a 30-day audit of all residential properties above four stories that are 40 years old or older and “have not completed the process to identify and address any issues.”The county is collaborating with partners in 34 cities of Miami-Dade County to conduct reviews on buildings that meet this criteria, Levine Cava said Wednesday.”We are going to get inputs and develop a set of recommendations for changes that need to be made here in the building process at the local level to ensure that this tragedy can never ever happen again.” Levine Cava told reporters.State Attorney Katherine Fernandez Rundle also said in a statement Tuesday that she will pursue a grand jury investigation into the collapse, adding that the grand jury helped issue a report during the aftermath of Hurricane Andrew in 1992. “I plan to request that our Grand Jury look at what steps we can take to safeguard our residents without jeopardizing any scientific, public safety, or potential criminal investigations,” Fernandez Rundle said in the statement.Biden supports a federal probe into the matter, Psaki said this week.This is developing news. Please check back for updates.—Reuters contributed to this report.