Mickey Mouse is living on swiss cheese. The fact is Florida — where the highest natural point, Britton Hill at 345 feet, is so low that buildings built at sea level are taller — has a conglomerate of carbonate sediments that in some locations make the formation of sinkholes a common problem.
Beginning last night at around 10:30 p.m. with windows cracking, a significant portion of a three-story resort villa, about five miles from Disney World in Orlando, finally collapsed at 3 a.m. this morning as a 60-foot wide crater developed. Residents evacuated safely, albeit with some escaping through windows rather than doors.
Florida has four types of sinkhole risk regions with the greatest number of the scariest type – quick forming, cover-collapse sinkholes – occurring in the central region of the state. It’s here where clay sediments of 30 to 200 feet thick overlay the limestone. When holes in the the limestone form, the clay sediment forms a bridge over those holes that can remain in tact for some time before dramatically collapsing and forming a sinkhole.
Cover-collapse sinkholes are less common along most of the southwestern part of the Panhandle where sediment cover can be more than 200 feet thick. But in this same region when sinkholes do form, they can become very large and deep.
In the southern portion of the state around Miami, sinkholes are few, slow to form, shallow, but also very wide, because the sediment layer above the limestone bedrock is thin, if it is there at all. In this situation, when a sinkhole grows it usually happens gradually, is easily detected, and often occurs after a rainstorm as a result of the slightly acidic water dissolving the limestone ground.
Sinkholes in Florida are few, slow to form, shallow, and small along most of the eastern Atlantic seaboard. Here sediment cover is again some 30 to 200 feet thick, but instead of clay, it is mostly sand overlying the limestone. Rather than forming a bridge over any holes that develop, the sand, like in an hour-glass, flows at about equal time as the deformation occurs.
IMAGE: People look at a partially collapsed building over a sinkhole at Summer Bay Resort near Disney World on August 12, 2013 in Clermont, Florida. (Photo by Gerardo Mora/Getty Images)