Orographic clouds form when wind pushes air against a mountain or mountain range, forcing it to rise. As it ascends, the air cools adiabatically until it reaches its dew point and condenses. They include lenticular clouds, banner clouds (attached to peaks), and cap clouds.
Effect on precipitation
Orographic clouds drive orographic precipitation: the windward slope receives heavy rainfall while the lee side sits in a "rain shadow" with dry conditions. In Spain, this effect is clearly visible in the Pyrenees, the Cantabrian Range, and Sierra Nevada, where precipitation differences between slopes can exceed 1,000 mm per year.