Park rangers are frantically searching for a man who has been missing since Monday at the Great Smoky Mountains National Park.

A team of 47 rangers, assisted by local agencies, is scouring the park for Marcin Bachleda-Blaszczak, who was reported missing August 24, Great Smoky Mountains National Park said in a statement.

The Illinois man, who is described as being 5’6” and 170 lbs, was last seen at Sugarlands Visitor Center parking lot on the previous Saturday, which is where his car was found.

“As the search area expands, visitors may encounter search personnel wearing brightly colored shirts both on and off established trails,” the statement said.