The general high pressure relations which are outlined above last from August to April. Thus about half of Russia has a winter of six months' duration, while from Yenisei eastwards there stretches a vast area of permanently frozen ground extend ing from the Arctic to the south of lat. 5o° N. only southern Kamchatka and the Maritime provinces of the Far Eastern Area lying outside this zone, which extends westwards from the south of the Gulf of Taz to the open Murmansk coast. In this per manently frozen zone winter lasts 6 to 9 months or more and summer is too short to thaw the ground to any depth. Forest and tundra cover much of it, and in a few places, notably in the Yakutsk area there is some cultivation of potatoes and hardier cereals on the upper, temporarily thawed soil above the permanently frozen subsoil. The line marking the southern limit of the duration of winter for a period varying from 3 to 6 months extends westwards from the Tian Shan, passing well to the south of the Sea of Aral and crossing the Caspian and the Sea of Azov, so that their northern portions lie within it, and just skirting the north of the Black Sea. The effect of this prolonged winter on the life of the people is profound; agricultural and outdoor occu pations (e.g., building) are impossible, river navigation ceases and sledge transport takes its place. Terrible wind and snow storms occasionally sweep with great violence across the plains even in the southern steppe and the Ukraine, and cattle and sheep perish in great numbers.
In a great country depending mainly on agriculture this prolonged annual pause constitutes a very serious drawback. Its complex psychological and physical effects on the individual are also profound, especially when monotonous diet and insuffi cient vitamin supply accompany it. For an interesting account of the effects of severe climate on human personality see Cza plicka, Aboriginal Siberia, 1914. The deterioration of the tribes pushed to the north-east and of the Russian settlers in Kam chatka are patent and extreme cases and the slow cultural de velopment of the Russian race must be in part attributed to climatic causes. The only regions with a winter frost of one month or less are the south-east coast of the Crimea, the malarial east coast strip of the Black Sea and the arid coastal regions of the eastern and western shores of the South Caspian. The Lenkoran district of the south-west Caspian shore, with an annual rainfall averaging 4o inches is an interesting example of micro-climate due to local relief. The warm Atlantic drift influences the winter of European Russia and her only all the year round open port is the recently built Murmansk on the Arctic coast. The prevailing westerly winds modify winter conditions in north and central European Russia, so that winter isotherms have a general north west to south-east trend. The coldest winter in the world (as yet recorded) is experienced at Verkhoyansk in lat. 67° 30' N., E., 3,00o miles east from the Atlantic, where the average January temperature is —59° F, and where it dropped to —9o° F in February 1892, the lowest temperature ever observed.
There is no direct insolation in winter, since it lies within the Arctic circle, night radiation from the snow covered earth is intense in the clear, dry atmosphere and, as Verkhoyansk lies in a valley bottom, inversion of temperature intensifies the cold.
Woeikof attributes the fact that Sagastyr on the Arctic Ocean, in 73° 32' N. has an ay. Jan. temp. 25° F warmer than that of Verkhoyansk to the stronger winds on the flat and treeless tundra and to the absence of temperature inversion. S. Obruchev ("Dis covery of a Great Range in North-Eastern Siberia," Geographical Journal, 1927, vol. 70) suggests that the Pole of Cold may extend over the Upper Indigirka. Another local relief effect is the cold temperature experienced immediately east of the Scan dinavian mountains. A general feature of the Russian winter south of the Arctic circle is the clear bright sunshine and the absence of cloud, the maximum of cloudiness being experienced in autumn, except in the Far Eastern Area, where summer is the season of maximum cloud, and in the south of the Ukraine. the Kazakstan steppe.and the Central Asiatic Republics where winter, though not very cloudy, is the season of greatest nebulosity. In three regions, the western Caucasus and west trans-Caucasia, the district between Lake Balkhash and the Tian Shan and in a belt on the left bank of the Amur from Blagovyeschensk to its mouth, spring is the cloudiest season. The general prevalence of clear skies in spring is a noticeable feature.