The Urals divide into five sections. The northernmost Polar Urals extend some 240 miles from Mount Konstantinov Kamen in the northeast to the Khulga River in the southeast; most mountains rise to 3,300-3,600 feet (1,000-1,100 metres) above sea level, although the highest peak, Mount Payer, reaches 4,829 feet.
The next stretch, the Nether-Polar Urals, extends for more than 140 miles south to the Shchugor River. This section contains the highest peaks of the entire range, including Mount Narodnaya (6,217 feet [1,895 metres]) and Mount Karpinsk (6,161 feet).
These first two sections are typically Alpine and are strewn with glaciers and heavily marked by permafrost.
Farther south come the Northern Urals, which stretch for more than 340 miles to the Usa River in the south; most mountains top 3,300 feet, and the highest peak, Mount Telpos-Iz, rises to 5,305 feet.
Many of the summits are flattened, the remnants of ancient peneplains (eroded surfaces of large area and slight relief) uplifted by geologically recent tectonic movements. In the north, intensive weathering has resulted in vast "seas of stone" on mountain slopes and summits.
The lower Central Urals, extending more than 200 miles to the Ufa River, rarely exceed 1,600 feet, though the highest peak, Mount Sredny Baseg, rises to 3,261 feet. The summits are smooth, with isolated residual outcrops.
The last portion, the Southern Urals, extends some 340 miles to the westward bend of the Ural River and consists of several parallel ridges rising to 3,900 feet and culminating in Mount Yamantau, 5,380 feet; the section terminates in the wide uplands (less than 2,000 feet) of the Mughalzhar Hills.
The rock composition helps shape the topography: the high ranges and low, broad-topped ridges consist of quartzites, schists, and gabbro, all weather-resistant. Buttes are frequent, and there are north-south troughs of limestone, nearly all containing river valleys. Karst topographyis highly developed on the western slopes of the Urals, with many caves, basins, and underground streams.
The eastern slopes, on the other hand, have fewer karst formations; instead, rocky outliers rise above the flattened surfaces. Broad foothills, reduced to peneplain, adjoin the Central and Southern Urals on the east.
The Urals date from the structural upheavals of the Hercynian orogeny (about 250 million years ago). About 280 million years ago there arose a high mountainous region, which was eroded to a peneplain. Alpine folding resulted in new mountains, the most marked upheaval being that of the Nether-Polar Urals.
In the watershed region lies the Ural-Tau Anticlinorium (a rock formation of arches and troughs, itself forming an arch), the largest in the Urals, and in the Southern Urals, west of it, is the Bashkir Anticlinorium. Both are composed of layers (sometimes four miles thick) of ancient metamorphic (heat-altered) rocks-gneisses (metamorphic rocks separable into thin plates), quartzites, and schists-that are between 570 and 395 million years old.
The western slope of the Urals is composed of middle Paleozoic sedimentary rocks (sandstones and limestones) that are about 350 million years old. In many places it descends in terraces to the Cis-Ural depression (west of the Urals), to which much of the eroded matter was carried during the late Paleozoic (about 300 million years ago). Found there are widespread karst (a starkly eroded limestone region) and gypsum, with large caverns and subterranean streams.
On the eastern slope, volcanic layers alternate with sedimentary strata, all dating from middle Paleozoic times. These rocks compose the Tagil-Magnitogorsk Synclinorium (a group of rock arches and troughs, itself forming a trough), the largest in the Urals. In the Central and Southern Urals the eastern slope blends into broad peneplained foothills, where there are frequent outcrops of granite and often fantastically shaped buttes. To the north the peneplain is buried under the loose, easily pulverized deposits of the West Siberian Plain.
The rivers flowing down from the Urals drain into either the Arctic Ocean or the Caspian Sea. The Pechora River, which drains the western slope of the Polar, Nether-Polar, and part of the Northern Urals, empties into the Barents Sea. Its largest tributaries are the Ilych, Shchugor, and Usa.
Almost all the rivers of the eastern slope belong to the Ob River system, emptying into the Kara Sea. The largest are the Tobol, the Iset, the Tura, the Tavda, the Severnaya (Northern) Sosva, and the Lyapin.
The Kama (a tributary of the Volga) and the Ural rivers belong to the drainage basin of the Caspian Sea. The Kama collects water from a large area of the western slope: the Vishera, Chusovaya, and Belaya all empty into it. The Ural River, with its tributary the Sakmara, flows along the Southern Urals.
The location and character of the Urals' rivers and lakes are closely connected with the topography and climate. In their upper reaches many rivers flow slowly through the mountains in wide, longitudinal troughs. Later they change to a latitudinal direction, cut through the ridges in narrow valleys, and descend to the plains, particularly in the Northern and Southern Urals. The main watershed does not correspond with the highest ridges everywhere. The Chusovaya and Ufa rivers of the Central and Southern Urals, which later join the Volga drainage basin, have their sources on the eastern slope.
The rivers on the western slope carry more water than those of the east, particularly in the Northern and Nether-Polar Urals; the slowest rate of flow is on the eastern slope of the Southern Urals, reflecting intense evaporation as well as low precipitation. In winter the rivers freeze for five months in the south and for seven months in the north.
There are many lakes, especially on the eastern slope of the Southern and Central Urals. The largest are Uvildy, Itkul, Turgoyak, and Tavatuy. On the western slope are many small karst lakes. In the Polar Urals, lakes occur in glacial valleys, the deepest of them being Lake Bolshoye Shchuchye, at 446 feet deep. Medicinal muds are common in a number of the lakes, such as Moltayevo, and spas and sanatoriums have been established.
The climate is of the continental type, marked by temperature extremes that become increasingly evident both from north to south and from west to east.
The Pay-Khoy Range and the Polar Urals enjoy the moderating influence of the Arctic and the North Atlantic oceans, particularly in winter. In the Mughalzhar Hills and the Southern Urals there are summer winds of hot, dry air from Central Asia. Winds are for the most part westerly and bring precipitation from the Atlantic Ocean.
In spite of their low elevation, the mountains exert a considerable influence on the moisture distribution, and the western slope receives more moisture than the eastern. Precipitation is particularly heavy on the western slope of the Nether-Polar and Northern Urals, as high as 40 inches (1,000 millimetres). Northward and southward precipitation diminishes to about 18 inches. On the eastern slope there is less moisture (about 12 inches) and snow. Annual snow depth on the western slope averages 35 inches and on the eastern, 18 inches. Maximum precipitation occurs in the summer, for the cold, dry air of the Siberian anticyclone is powerful in winter.
The eastern slope is particularly chilled, and winter lasts longer than summer throughout the Urals. In January the average temperature in the north is -6° F (-21° C), and in the south the average is 5° F (-15° C). Average temperatures in July vary more, between 50° F (10° C) in the north and 72° F (22° C) in the south.
The Urals pass through several vegetation zones, with the northern tundra giving way to vast mixed forests, while still farther south is the steppe, culminating in semidesert around the Mughalzhar Hills. Feather grass and meadows predominate on the chernozems (black earth) and dark chestnut soils (a characteristic steppe soil). Other characteristic growths are clover, fescue (a pasture grass), and timothy (a grass grown for hay). South of the Ural River the steppes give way to wormwood and semidesert growths on light chestnut soils (again typical steppe soil), which are highly saline in places.
The forest landscapes of the Urals are varied. The more humid western foothills of the Southern Urals are covered mostly by mixed forests growing on a gray mountain-forest type of soil. There, such broad-leaved species as oak, small-leaf linden, and elm are mixed with Siberian fir and Siberian spruce. The broad-leaved forests extend to 2,100 feet, above which conifers appear. On the eastern slope there are no broad-leaved trees except the linden, and magnificent pine forests with some larches are widespread.
Farther to the north, in the Central Urals, boreal forests (taiga) of spruce, fir, pine, and larch grow on the mountain, podzolic soils. In the more northerly regions, dark conifers are common, and, in the Northern Urals, the Siberian cedar is widespread. There forests climb to 2,800 feet or so, above which is a narrow belt of larch and birch, trailing off to mountain tundra.
In the Nether-Polar and Polar Urals the forest yields to mountain tundra at elevations as low as 1,300 feet. Whereas moss tundra is generally found on the more humid western slope, lichen tundra is common on the eastern. There are numerous sphagnum moss marshes on both slopes. Only brushwood and moss-lichen tundra grows on the Pay-Khoy Ridge.
There are no specifically mountain animals in the Urals, primarily because of the low elevations and easy accessibility, and fauna differs little from that of the adjacent areas of Eastern Europe and western Siberia.
The most valuable animal of the tundra is the Arctic fox. Ob lemmings, snowy owls, tundra partridge, and reindeer are other inhabitants, though the latter are few. Many wild ducks, geese, and swans breed there in summer. But the richest and most varied fauna in the Urals, including the brown bear, lynx, wolverine, and elk, are found in the forested zones. Some have valuable furs: the sable (in the north), ermine, fox, marten (in the south), Siberian weasel, and squirrel.
In the taiga there are such birds as the wood grouse, black grouse, capercaillie (another member of the grouse family), cuckoo, and hazel hen (a woodland grouse). In the mixed, broad-leaved forests of the Southern Urals' western slopes live roe deer, badgers, and polecats, as well as many birds typical of the European part of Russia, such as the nightingale and oriole.
The commonest animals of the steppe and semidesert regions are rodents, including susliks (a type of ground squirrel), jerboas (a social, nocturnal, jumping rodent), and other agricultural pests. Reptiles include the common adder and grass snake.
The rivers and lakes of the Northern Urals abound in fish, the most valuable being the nelma (aspecies related to the whitefish), common salmon, grayling, and sea trout. Farther south, in the densely populated and industrial regions, animal life is less abundant.
The vigorous economic development and growth in population that have occurred in the Urals in the 20th century have altered considerably the chain's landscape and the abundance of wildlife. Conservation measures during the Soviet period included establishing national nature preserves such as Pechoro-Ilych in the Northern Urals, Basegi and Visim in the Central Urals, and Ilmen and Bashkir in the Southern Urals.