We received several photos and questions about interesting cloud formations in the sky over parts of the Triangle Sunday afternoon. These clouds appeared almost wave like, so it is appropriate that they are caused by something meteorologists call gravity waves.

Sunday afternoon in Chapel Hill. Photo by Marianne CK.

Our atmosphere acts much like a fluid, and these gravity wave clouds form very similar to if you were to throw a rock in a lake. The rock hitting the lake surface would cause ripples in the water extending from where the rock made impact. Gravity waves cause up and down motion rippling through the atmosphere. The areas of downward motion create clearing giving a wave-like appearance to the clouds.

The up and down motion in the atmosphere needs to be triggered by something like throwing a rock in the water. There are a few things that can make that happen. On Sunday, it was likely caused by a cold front that was moving through North Carolina.

Air flowing over mountains can also cause gravity waves. They can also be much more serious that just interesting clouds. Gravity waves can create turbulence for aircraft.

Do you have any interesting weather photos to share with us? Share then with Meteorologist Lee Ringer on Facebook or e-mail your photos to ncweather@charter.com