A hole more than 20m wide and 17m deep has opened in a northwestern suburb of the city in the US state of Florida, and has started swallowing a house, local media are reporting.
Nearby residents were evacuated as cracks, pops and crashes started emanating from the hole.
The sinkhole straddles two back yards and the ground is so unstable that both homes need to be demolished, a Fire Department spokesman said.
Mike Dupre, whose house is the one being swallowed, said his daughter noticed something was wrong early in the morning.
"She woke us up and saved us," he said.
He stepped out on to his porch and found it already had sunk 1m into the ground.
"We needed to get out of the house as fast as possible," he said.
As the hole grew, it swallowed the porch and a new boat.
His neighbour's swimming pool and a portion of that house have fallen in, too.
Engineers were called in and decided both Dupre's home and his neighbour's would be complete losses.
A digger was used to pull Dupre's boat from the hole. Crews had feared fuel in the boat would leak into groundwater. Otherwise, the rescue crews are in a holding pattern until the hole stabilizes.
The fire deprtment spokesman said it was not clear what caused the hole, but Dunedin had a history of sinkhole activity and sinkholes were not uncommon in west-central Florida.
