Another sinkhole has opened up, this time in Pennsylvania.

The gaping hole in the ground appeared as Doris Jenkins left her home in Bethlehem Township Sunday morning to walk her dog. She was soon surprised to find that a large 40-foot hole had begun to form in her driveway.

"I wasn't thinking that this was how I was going to be spend my Sunday afternoon," daughter Inga Jenkins told NBC. Fortunately, Doris, Inga and granddaughter Claudia Jenkins were able to leave uninjured.

Jenkins' house does have some cracks in the foundation and potential roof damage. For now they are required to remain outside the home, partly due to the fumes emanating from the sinkhole. Neighbor Courtney Smith was also told she may have to evacuate.

"Everybody in the house has bags ready to go," she said.

The cause of the sinkhole is unknown, though workmen had been repairing a sewer line break not far away at the time. At least two additional sinkholes formed on a smaller scale nearby.

According to the Pennsylvania Department of Environmental Protection, sinkholes are caused by water dissolving rock like limestone and dolomite. When water and carbon dioxide combine into acid, the rock is then eaten away. This results in a sort of underground cavern, compromising the stability of the ground.

"As the cavern is growing, the support for the ground above decreases and eventually what happens is that land eventually subsides, settles or falls into this cavity," Franklin Institute geologist and chief astronomer Derrick Pitts said.

According to the Pennsylvania Department of Conservation and Natural Resources, sinkholes are a large hazard in the state. They state that seven percent of the state's land is sinkhole-vulnerable.

Sinkholes have been somewhat prominent in the news lately. Just over a week ago a Florida man was killed after a sinkhole opened in Florida.