Engineers and county authorities described what they called an unprecedented situation in Seffner Friday evening: a sinkhole expanding into an underground chasm, and likely to keep growing.
Deputy Douglas Duvall, the first person on the scene and inside the house, said he saw a hole in the ground that had swallowed an entire bedroom, and was still growing.
"Everything was sinking," Duvall said.
Bill Bracken, an engineer who is part of Hillsborough County's urban search and rescue team, estimated that the sinkhole went from a depth of 15 feet to 25 feet in a matter of minutes.
Larry Madrid, another engineer at the scene, said that's because there were essentially two collapses of the earth under the home.
Madrid explained why authorities are calling the sinkhole extremely unstable: the side of it are still very steep, and the soil around the hole is soft. He said that the sides would likely continue to collapse into a diagonal angle before the sinkhole would be done growing.
In the meantime, the job at hand now is to figure out what the "soft zone" is: meaning, how far out does the soft soil go, and where is the edge where crews can safely set up equipment?
They could not provide a timetable as to when that would be.
But they left little doubt about the dangerous conditions around the house, and expressed surprise it was even still standing.
"I can't tell you why the house hasn't collapsed yet," Madrid said. "It should have collapsed by now."