Sinkholes are nothing new in Florida. Thousands of them develop each year. Dozens of them swallow buildings.
Deaths, however, are very rare.
Authorities believe a man near Tampa died Thursday when a sinkhole opened up under his house, swallowing the bed in which he was sleeping. Jeffrey Bush, 37, could not be found Friday, even after his brother and emergency officials raced to save him.
Anthony Randazzo said the tragic episode was incredibly rare.
Randazzo has made a career studying sinkholes, first as a professor at the University of Florida and now through his company, Geohazards, Inc., which analyzes potential sinkholes and seals them up.
He only recalls two other people who died because of a sinkhole in the 40 years he's been involved with the geological phenomenon. And in both those cases - both in Florida - Randazzo said the people were drilling water wells and triggered the sinkholes to open underneath them.
"Usually, you have some time," said Randazzo, who has lectured on sinkholes at Oxford University. "These catastrophic sinkholes give you some warning over the course of hours. This is very unusual and very tragic."
Sinkholes are a fairly common occurrence not just in Florida. There have been many cases of massive sinkholes developing in different areas around the country, including:
In November, a sinkhole the size of four football fields opened outside the town of Dover, Ohio, and tore up State Route 516. State transportation officials said it would take several months to repair the road.
In August, an 8.6-acre sinkhole developed over a mining operation in southeastern Louisiana that prompted the evacuation of 150 homes nearby and filled the hole with oil and natural gas. The state legislature is now holding hearings to determine how much Texas Brine Co., LLC, the owner of the mine, must reimburse the homeowners.
In 2008, a 900-foot wide sinkhole in Daisetta, Texas, swallowed a tractor, oil field equipment, several vehicles and telephone poles. The hole filled with groundwater and an alligator moved in from a nearby swamp.
In 2002, a sinkhole developed under a barn in Sanford, Fla., collapsing the structure and killing two horses.
Sinkholes typically form when the ground beneath an area slowly dissolves and can no longer support the weight above it. Areas with limestone underneath the surface are highly susceptible because of how easily it dissolves.
There are several ways to spot a developing sinkhole. According to the Southwest Florida Water Management District, slumping or sagging fence posts or trees are a clear sign. Doors and windows that don't close properly and small ponds of rainfall forming where water has not collected before are also signs.
Randazzo said many developing sinkholes can be stopped. His company injects grout into the area to fill the cracks developing underground and shore up the foundation.
"It's similar to a dentist filling a cavity," he said. "It sets and hardens and stabilizes it."