Surfside building collapse: Biden to visit victims' families as death toll rises, 145 are still missing

One week after a building in Surfside, Florida, collapsed, rescue crews are still searching for survivors, and questions about what caused the tragedy remain unanswered.

One week after a residential building in Surfside, Florida, collapsed, rescue crews are still searching for survivors, and questions about what caused the tragedy remain unanswered. As of Thursday morning, 18 people -- including two children, ages 4 and 10 -- have been pronounced dead and 145 others remain unaccounted for. "Any loss of life, especially given the unexpected, unprecedented nature of this event is a tragedy," Miami-Dade mayor Daniella Levine Cava said, announcing the deaths of the two children during a Wednesday evening press briefing. "But the loss of our children is too great to bear." Florida officials are now eyeing and developing a contingency plan for a potential tropical storm in the Atlantic Ocean, which could hinder the search and rescue mission. Crews have already been impacted by intermittent bad weather that caused temporary delays in the work.