Written by Meteorologist Chris SpearsDENVER (CBS4) – Several CBS4 viewers caught a really cool cloud formation late Friday evening over Breckenridge.

Stacy Nicholson & Skip Wood, visiting Colorado from Moorhead, Minnesota, wrote saying they’ve never seen anything like it.

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These clouds are known as Kelvin-Helmholtz instability clouds, named for Lord Kelvin and Hermann von Helmholtz, and they are formed due to wind shear in the atmosphere.

Wind shear is a change in either speed, direction, or both over a short distance.

The wind shear creates waves in the flow of air and when there is enough moisture present to make a cloud, the result is little rolling eddies seen along the top of the cloud.

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These eddies are usually evenly spaced and easily identifiable and often don’t last too long.

Kelvin-Helmholtz instability clouds are most commonly seen in mountainous areas and they indicate extreme turbulence for aircraft.

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Meteorologist Chris Spears writes about stories related to weather and climate in Colorado. Check out his bio, connect with him on Facebook or follow him on Twitter @ChrisCBS4.