Making waves above the Outeniquas

GEORGE NEWS - This Kelvin-Helmholtz cloud formation above the Outeniqua Mountains was photographed by MC Lamprecht near the airport crossing on the R404 just after 14:00 on Friday 17 June.

Lamprecht was on his way home from Herold's Bay when he noticed the extraordinary clouds. He immediately pulled over and by the time he finished taking the snaps, the clouds had all but flattened out.

These beautiful clouds that look like waves are extremely rare. Also known as billow clouds, or shear-gravity clouds, earthsky.org says they may have been the inspiration for Van Gogh's painting Starry Night.

Earthsky.org provides the following information:

"Kelvin-Helmholtz clouds are named for Lord Kelvin and Hermann von Helmholtz, who studied the physics of the instability that leads to this type of cloud formation. A Kelvin-Helmholtz instability forms where there's a velocity difference across the interface between two fluids: for example, wind blowing over water.

"When might you get to see these beautiful clouds? Your odds are better on windy days, when there's a difference in densities of the air - for example, during a temperature inversion - when warm air flows over cooler air.

"You're also more likely to see these clouds near sunrise or sunset, another time when the bottom of the clouds are cooler and the air above is warmer. The clouds take on this wave shape when the air above is moving more quickly than the air below, pushing over the tops of the clouds and creating the rolling wave appearance.

"As you might have guessed, Kelvin-Helmholtz clouds are a sign that aircraft in the area will be experiencing turbulence."

Clouds resembling waves float above the Outeniqua Mountains.