The rain shadow effect is a result of relief rainfall. Relief rainfall occurs when moisture laden air is forced to rise because of a mountain or mountain range. As the winds approach the range acts as a barrier causing the moisture laden air to rise. Once air rises it cools and condensation occurs. This leads to precipitation on the windward side of the mountain. The air then begins to descend down the leeward side. This air is however dry and contains little moisture leading to minimal rainfall to regions on the leeward side. This area is called the rain shadow zone and Iran and Turkey are located in such an area.
