A more recent update has the death toll at three, and 99 people are presumed missing. I would have to add that that 99 number is likely problematic — who knows where it came from. There could be people who were on vacation or otherwise out of town. I expect that number could go lower in the coming days; however, I also expect the death toll to go up.
The only good news I can report is that there are two Urban Search and Rescue (US&R) Task Forcesin the immediate Miami area. These teams are highly trained in doing search and rescue operations in exactly this type of situation. If they can find a survivor who is trapped, they will move heaven and hell to get to them.
Here is more information on the US&R Teams.