You just might hear it before you see it.

From a distance, the prop noise of the MH-53M Pave Low IV resembles that of other helicopters that occasionally buzz above the Roanoke Valley.

Once it comes closer, though, there’s no mistaking the sight or sound of a Pave Low for Lifeguard 10.

With its gray shell, its sloped front windows and its nose-mounted refueling probe, the thing looks like an 88-foot-long Teflon dragonfly.

Through June 5, three of these Sikorsky-built behemoths will periodically cruise over Southwest Virginia, but they do not signal an enemy invasion.

They’re part of the U.S. Air Force’s 20th Special Operations Squadron within the 1st Special Operations Wing. Members of the 20th SOS, also called the Green Hornets, will be operating out of Roanoke Regional Airport for the next week as they run training exercises.

This region has terrain that, according to Maj. Brian Roberts, resembles that of "Afghanistan [or] Columbia. It could be any area around the world that's mountainous."

Read the story.