Cover-collapse sinkholes can open up suddenly.
Detailed Description
Cover-collapse sinkholes
Cover-collapse sinkholes may develop abruptly (over a period of hours) and cause catastrophic damages. They occur where the covering sediments contain a significant amount of clay. Over time, surface drainage, erosion, and deposition of sinkhole into a shallower bowl-shaped depression.
Sources/Usage
Public Domain.
Related
Sinkholes
It is a frightening thought to imagine the ground below your feet or house suddenly collapsing and forming a big hole in the ground. Sinkholes rarely happen, but when they strike, tragedy can occur. Sinkholes happen when the ground below the land surface cannot support the land surface. They happen for many reasons; read on to educate yourself about sinkholes.
Related
Sinkholes
It is a frightening thought to imagine the ground below your feet or house suddenly collapsing and forming a big hole in the ground. Sinkholes rarely happen, but when they strike, tragedy can occur. Sinkholes happen when the ground below the land surface cannot support the land surface. They happen for many reasons; read on to educate yourself about sinkholes.