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.

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.

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.