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.
ANALYSIS: What Is A Sinkhole?
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.