hole punch cloud in NC
© PHIL LAMBERT/WBTV
What is this? The photo was taken on Old Mountain Road in Iredell County. Several images of the same thing have appeared on Facebook.
Images showing a mysterious circular gap that appeared in the clouds over a North Carolina highway have ignited a scramble for explanations on social media, including the possibility it was created by a UFO.

North Carolina TV station WBTV was the first to post a photo on Monday, with an explanation that viewer Phil Lambert of Lenoir submitted the photo taken on Old Mountain Road in Iredell County.

The photo shows what appears to be a near perfect circle in the clouds.

Not long after, photos from other people began to appear on Facebook, with some commenting — perhaps tongue-in-cheek — that the shape was not unlike the gap that might be left by a descending flying saucer ... or a cloaked USS Enterprise (a Star Trek reference.)

"ALIENS!" wrote Dan Ciaccio on Facebook.

"Wow! Looks like a scene from Independence Day!," posted Jennifer Brady Ellis, referring to the 1996 alien invasion movie.

Kathy Lynn Carlin of Collettsville, N.C., was among those who shared photos on Facebook. She told McClatchy news group she and her husband saw the odd formation around 10 a.m. Saturday, as they drove to Statesville on N.C. 64/90. That's about 65 miles northwest of Charlotte.

She watched for 10 minutes, long enough to see the hole begin to develop an even stranger looking funnel cloud appearance at its center, she said.

"Can someone please explain to me what exactly this is," she posted on Facebook.

"We rounded a curve ... and it was directly in front of us," Carlin told McClatchy news group. "We thought it looked like a tornado, but didn't see any rotation."

Experts believe a likely explanation is that it was a fallstreak or hole punch cloud, a weather phenomenon that has resulted in reports of UFOs in other parts of the country, according to Earthsky.org.

Hole punches are created when "supercooled" water droplets turn to ice crystals after coming into contact with passing planes, the National Weather Service reports. The frozen droplets start to fall, creating a hole that expands "outward as neighboring droplets start to freeze,"the NWS says.

"They look like strange clearings in an altocumulus cloud layer, often circular patches of clear sky, surrounded by clouds," reports Earthsky.org. "Sometimes people report them as UFOs."

In January, the National Weather Service office based in Seattle tweeted that multiple "fallstreak hole clouds" formed over British Columbia, resulting in an MSN.com report of "scary, strange cloud patterns" that resembled a "UFO invasion."