Orographic lifting
When a warm, moist wind blows against a mountain range, it begins to climb up the mountainside. During this ascent it cools adiabatically and after cooling below the dew point, orographic clouds are formed. These are of the stratus type. If the mountain is quite high, further ascent results in nimbostratus and continuous precipitation. On the windward side of the mountain peak, clouds are forming steadily whereas in the leeward side, they are dissipating at the same rate (while descending, the air warms up adiabatically and the clouds evaporate). It therefore appears as if a stratiform cloud is stationary over the mountain peak. In Greek, the word “Oros” means mountain.
