Orange County Fire Rescue Battalion Chief Billy Richardson said the sinkhole developed while residents of the property in Winter Park were out, the Orlando Sentinel reported. He said by the time emergency workers got to the house at 8:30 p.m. Monday the hole was 40 to 50 feet wide and 30 to 40 feet deep.
"They came back from dinner and half the backyard was gone," Richardson said.
There were no signs of trouble Sunday when the owner, identified on county records as Suzanne Blumenaur, had a pool party, neighbors said.
Sinkholes are common in Florida where the limestone underlying most of the state dissolves, forming underground cavities. They are often covered with soil and vegetation that can collapse suddenly.
Fatalities are unusual. In February, a man disappeared when a sinkhole developed late at night under a home in Seffer near Tampa.