What Caused This Awesome Cloud Over Breckenridge Friday?

DENVER (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 distanc