There's a terrifying story from Florida this morning.
"A sheriff's deputy plucked a man from an expanding sinkhole Thursday night, but neither was able to save the man's brother from being sucked into the rubble, authorities said," the Tampa Bay Times writes.
Tampa's ABC Action News reports that "Hillsborough County Fire Rescue officials say the victim, Jeff Bush, is presumed dead." The Times' online headline early Friday said rescue hopes were "dim."
CBS News adds that "Fire rescue spokeswoman Jessica Damico said Bracken Engineering officials determined the home's bedroom is the center of the sinkhole, which measures about 100 feet across. Listening devices and cameras were placed in the hole but there had been no contact with the missing man by early Friday." (Note at 10:10 a.m. ET: Authorities at the scene just told reporters that the hole is 30-feet in diameter and about 20 feet deep. They have established a 100-foot "safety zone" around the hole, but it is not that wide.)
As the Times writes, "although it has proven somewhat common for sinkholes to open in Central Florida and swallow cars and houses, it is not at all common for people to become trapped in them."
Why does this happen? The Florida Department of Environmental Protection says that:
"Sinkholes form in karst terrain principally from the collapse of surface sediments into underground voids and cavities in the limestone bedrock. Slightly acidic ground water slowly dissolves cavities and caves in the limestone over a period of many years. When the cavity enlarges to the point that its ceiling can no longer support the weight of overlying sediments, the earth collapses into the cavity. In the less catastrophic type of sinkhole, a bowl-shaped depression forms at the surface, usually over a considerable period of time, as surface sediments ravel downward into small cavities in the bedrock. Well drilling data suggests that much of the underlying bedrock in Florida contains cavities of differing size and depth. However, relatively few ever collapse and directly effect roads or dwellings."
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