Inside a Sinkhole: More Than What Appears at the Surface (Video)

Sinkholes are common and unpredictable in Florida. Two sinkholes opened up in Florida this week, and one man died. David Mattingly, CNN national correspondent, took a 50-foot trip down a sinkhole in Williston, Fla. 

Sinkholes are common in Florida. They can form gradually over time or suddenly with no warning, yet there is no system to predict a sinkhole. 

“Insurance companies have tried developing risk prediction methodology, but since the underground cavities are largely undetectable without expensive ground-penetrating radar surveys, resistivity tests, or test drilling, little real progress towards this goal has been made,” according to the Florida Geological Survey (FGS) with the Florida Department of Environmental Protection website.

However, property owners can hire professional geologists and geotechnical engineering consultants with professional geologists on staff to conduct tests to try to find buried cavities that might form sinkholes. But according to the FGS, the tests are very expensive and not always conclusive. 

Signs of a sinkhole directly impacting a structure is sinking, sagging, or cracking walls. If those signs are visible, the FGS recommends that you and others should stay out of the structure. 

In Florida, the FGS recommends contacting the property’s insurance adjuster and reporting the hole immediately. It can be reported to local government agencies, the Florida Division of Emergency Management, and the local water management district. The state also has a special report form—the Subsidence Incident Report Form—specifically for reporting sinkholes.