Spurs of the Greater and Lesser Caucasus ranges, separated by the Kolkhida lowland, confine the Black Sea in the east, while the Pontic Mountains run along the southern coast.Near the Bosporus outlet, the shoreline relief is moderate though still steep.
In winter, spurs of the Siberian anticyclone (a clear, dry, high-pressure air mass) create a strong current of cold air, and the northwestern Black Sea cools down considerably, with regular ice formation.
The winter invasion of polar continental air (which prevails for an average of 185 days annually) is accompanied by strong northeasterly winds, a rapid temperature drop, and frequent precipitation, with the air becoming warm and moist after passing over the milder eastern portions of the sea.
In ancient Greek myths, the sea—then on the fringe of the Mediterranean world—was named Pontus Axeinus, meaning “Inhospitable Sea.” Later explorations made the region more familiar, and, as colonies were established along the shores of a sea the Greeks came to know as more hospitable and friendly, its name was changed to Pontus Euxinus, the opposite of the earlier designation.
It was across its waters that, according to legend, Jason and the Argonauts set out to find the Golden Fleece in the land of Colchis, a kingdom at the sea’s eastern tip (now Georgia).
Between the port cities of Sinop and Samsun (Turkey), the coastline is paralleled by a rugged range of underwater mountains extending for nearly 100 miles (160 km).