The Bekaa is a fertile valley in Lebanon, located about 30 km (19 miles) east of Beirut. The valley is situated between the Mount Lebanon to the west and the Anti-Lebanon mountain ranges to the east. It forms the northeastern most extension of the Great Rift Valley, which stretches from Syria through the Red Sea into Africa. Bekaa Valley is about 120 km (about 75 miles) in length and has an average width of about 16 km (about 10 miles). It has a Mediterranean climate of wet, often snowy winters and dry, warm summers. The region receives limited rainfall, particularly in the north, because Mount Lebanon creates a rain shadow that blocks precipitation coming from the sea. Two rivers originate in the valley. the Orontes (Asi), which flows north into Syria and Turkey, and the Litani, which flows south and then west to the Mediterranean Sea. The Bekaa Valley vineyards are at an altitude of 1,000 meters, where the vines are sheltered by the surrounding mountains, resulting in an almost frost free climate with long mild summers and damp winters.