Timelapse footage of lenticular clouds caused by the passage of air over a mountain. The air rises over the mountain and sinks on the lee side, forming a wave downwind. The crests of this wave are above the level fot he dew point in the atmosphere, and standing waves form there, where the moist air condenses into lenticular clouds. Jet contrails show the seemingly smooth mountain wave has turbulent regions. Filmed in the US in the late afternoon in winter.