The formation of a possible sinkhole has closed part of the Vicksburg National Military Park.

Park officials said Union Avenue is closed to all through traffic, bikers and pedestrians included.

“Right now it seems to be developing,” Park Superintendent William Justice said. “There’s a depression in the pavement so as a result we really don’t know how big the hole underneath the pavement is. So we have closed off that section of Union Avenue between the arch and Pemberton.”

Access is still available to the Visitor Center and the parking lot, but visitors are asked to start their park tour at the Fort Hill Drive entrance. Those looking to exercise by walking or bicycling can enter the park at Confederate Avenue but are asked not to go south of Pemberton Avenue.

He said the park staff would reconsider these options Monday.

“If visitors want to tour as much of the park as they can, they can drive in on Confederate Avenue, cross at Pemberton and then come back up Fort Hill,” Justice said. “Or they can drive Confederate Avenue all the way over to the Visitors Center, but there will be no way to enter the tour road the normal way.”

A law enforcement ranger noticed the cracked and depressed pavement on Union Avenue near the Minnesota State Memorial and decided to close the area as a precaution. The ground has not opened up yet.

The park maintenance crew will assess the area Monday to decide the next steps that need to be taken. Until the assessment is made, Justice is not sure how the problem will be fixed or how long it will take to fix.

“The most important thing is to make sure the park is safe to our visitors and our employees and that the park is preserved for future generations,” Justice said. “So until we can be sure that it’s safe to drive through this section, or even to walk through this section, it will remain closed.”