where the terrain rises from sea level to over , enhancing precipitation due to orographic lift. The result is annual precipitation totals of over the southern interior to over near the southern and southeastern coasts. Some locations near these coasts where the terrain is particularly conducive to causing orographic lift receive up of precipitation per year. More precipitation falls in winter, when the storm track is most active, than in summer. The west coast of the central third of Greenland is also influenced by some cyclones and orographic lift, and precipitation totals over the ice sheet slope near this coast are up to per year. The east coast of the central third of the island receives between of precipitation per year, with increasing amounts from north to south. Precipitation over the north coast is similar to that over the central Arctic Basin. The interior of the central and northern Greenland Ice Sheet is the driest part of the Arctic. Annual totals here range from less than 100 to about 200 mm (4 to 8 in). This region is continuously below freezing, so all precipitation falls as snow, with more in summer than in the winter time. (USSR 1985). Ice-free seas The Chukchi, Laptev, and Kara Seas and Baffin Bay receive somewhat more precipitation than the Arctic Basin, with annual totals between ; annual cycles in the Chukchi and Laptev Seas and Baffin Bay are similar to those in the Arctic Basin, with more precipitation falling in summer than in winter, while the Kara Sea has a smaller annual cycle due to enhanced winter precipitation caused by cyclones from the North Atlantic storm track. The Labrador, Norwegian, Greenland, and Barents Seas and Denmark and Davis Straits are strongly influenced by the cyclones in the North Atlantic storm track, which is most active in winter. As a result, these regions receive more precipitation in winter than in summer. Annual precipitation totals increase quickly from about in the northern to about in the southern part of the region. Precipitation is frequent in winter, with measurable totals falling on an average of 20 days each January in the Norwegian Sea (USSR 1985). The Bering Sea is influenced by the North Pacific storm track, and has annual precipitation totals between , also with a winter maximum. Sea ice Sea ice is frozen sea water that floats on the ocean's surface. It is the dominant surface