and underground rivers that have a combined yield of thousands of liters per minute. Climate The most striking feature of the climate is the contrast. Between the humid Mediterranean coast and the arid desert regions lies a semiarid steppe zone extending across three-quarters of the country and bordered on the west by the Anti-Lebanon Mountains and the Jabal an Nusayriyah, on the north by the Turkish mountain region, and on the southeast by the Jabal al Arab, Jabal ar Ruwaq, Jabal Abu Rujmayn, and the Jabal Bishri ranges. Rainfall in this area is fairly abundant, annual precipitation ranging between . Most of the rain, carried by winds from the Mediterranean, falls between November and May. The annual mean temperatures range from in January to in August. Because the high ridges of the Jabal an Nusayriyah catch most of the rains from the Mediterranean, the Al Ghab depression, located east of these mountains, is in a relatively arid zone with warm, dry winds and scanty rainfall. Frost is unknown in any season, although the peaks of the Jabal an Nusayriyah are sometimes snow-covered. Farther south, rain-bearing clouds from the Mediterranean pass through the gap between the Jabal an Nusayriyah and the Anti-Lebanon Mountains, reaching the area of Homs and, sometimes, the steppe region east of that city. Still farther to the south, however, the Anti-Lebanon Mountains bar the rains from the Mediterranean, and the area, including the capital city of Damascus, becomes part of the semiarid climatic zone of the steppe, with precipitation averaging less than a year and with temperatures from in January to in July and August. The vicinity of the capital is, nevertheless, verdant and cultivable because of irrigation from the Barada River by aqueducts built during Roman times. In the southeast, the humidity decreases, and annual precipitation falls below . The scanty amounts of rain, moreover, are highly variable from year to year, causing periodic droughts. In the barren stony desert south of the Jabal ar Ruwaq, Jabal Abu Rujmayn, and Jabal Bishri ranges, temperatures in July often exceed . Sandstorms, common during February and May, damage vegetation and prevent grazing. North of the desert ranges and east of the Al Ghab depression lie the vast steppes of the plateau, where cloudless skies and high daytime temperatures prevail during the summer, but frosts, at times severe, are common from November to March. Precipitation averages a year but