Biden and First Lady Jill Biden held hands as they left the White House early for the flight to Miami and a trip to nearby Surfside, where the toll in the tragedy now stands at 18 dead, with more than 140 still unaccounted for.
The dead include two children, aged four and 10, Miami-Dade County Mayor Daniella Levine Cava said late Wednesday.
Any loss of life "is a tragedy," she said, "but the loss of our children is too great to bear."
Biden was scheduled to receive a briefing from Levine Cava and other state and local officials, thank first responders and search and rescue team members, and then have a private meeting with families of victims of the catastrophe.
Biden will "offer them comfort as search and rescue efforts continue," the White House said.
Officials said contingency plans were being put in place should a tropical cyclone now swirling in the Atlantic strengthen and strike the southern Florida coast next week, although the National Hurricane Center has said it is "too soon to determine what if any impacts could occur."