Orographic Effect

"How Do Mountains Affect Precipitation?

Cloud Formation
Mountains pose a significant obstacle to stable air flow. As air approaches the mountain it is forced upwards. At higher altitudes, the temperatures drop, condensing water vapor. This process results in the formation of clouds. Mountains may also restrict or slow down air flow. This restriction may also result in lifting air to high altitudes and creating clouds prior to the air reaching the slopes of the mountain.

Orographic Effect
As the air is forced higher by the mountain, the clouds that were formed eventually release water in the form of precipitation. This so-called orographic effect occurs because the clouds' ability to hold moisture lessens as temperatures drop. The higher the mountain, the lower the temperatures at its peak. This forces the clouds to release the precipitation in the form of thunderstorms in the summer and severe snowstorms in the winter. The orographic effect occurs on the windward side -- the side that faces the wind."

Sciencing, How Do Mountains Affect Precipitation?, 2018