White Sea

The White Sea cuts into Russia’s northwest coast as a southern arm of the Barents Sea. It is bounded by Karelia on the west, the Kola Peninsula to the north, and the Kanin Peninsula to the northeast. Entirely within Russian territory, it is classified as internal waters and split administratively among Arkhangelsk and Murmansk oblasts and the Republic of Karelia. Arkhangelsk, a key port on this sea, served for centuries as Russia’s primary hub for overseas trade, run by the Pomors from Kholmogory. Later, it became a major Soviet naval and submarine base. A canal, the White Sea–Baltic, links this sea to the Baltic. Along with the Black, Red, and Yellow seas, it is one of four bodies of water named after a common color term.

The International Hydrographic Organization sets the White Sea’s northern boundary as a line from Svyatoy Nos on the Murmansk Coast to Cape Kanin. The sea has four main bays, all connected to the Barents Sea through a funnel-shaped opening and a narrow strait called Gorlo—Russian for “throat.” Kandalaksha Gulf, in the west, is the deepest part at 340 meters. To the south, Onega Bay receives the Onega River. Southeast lies Dvina Bay, where the Northern Dvina flows into Arkhangelsk. On the east side of the gorlo, opposite the Kola Peninsula, Mezen Bay takes in the Mezen and Kuloy rivers. Other major rivers include the Vyg, Niva, Umba, Varzuga, and Ponoy.

The central seabed and Dvina Bay are covered in silt and sand, while the northern part, Kandalaksha Gulf, and Onega Bay have a mix of sand and stones. Ice age deposits often appear near the shores. Northwestern coasts are tall and rocky, but the southeastern side slopes more gently. Many small islands dot the sea; the largest group is the Solovetsky Islands, near the entrance to Onega Bay. Kiy Island in Onega Bay is notable for a historic monastery, and Velikiy Island, close to shore, is the biggest in Kandalaksha Gulf.

The White Sea sits in a depression on the Baltic Shield continental shelf. Its bottom is uneven, with the Kandalaksha Hollow in the northwest and the Solovetsky Islands in the south. Onega Bay has many small underwater rises. The sea’s opening and the gorlo are shallow, around 50 meters or less. An underwater ridge in the northern gorlo limits depths to 40 meters, restricting water exchange with the Barents Sea. Tides, which occur twice daily, help this exchange; their amplitude ranges from 1 meter in the south to 10 meters in Mezen Bay. Open-sea currents are weak, under 1 km/h, but strengthen in the bays. Tidal waves are faster, reaching 9 km/h in Mezen Bay, 3.6 km/h in Onega Bay, and 1.3 km/h in Kandalaksha Gulf.

Rivers deliver about 215 km³ of fresh water annually, mostly to Onega, Mezen, and Dvina bays. The Northern Dvina alone can contribute up to 171 km³ in some years, with the Mezen, Onega, Kem, and Vyg adding 38.5, 27.0, 12.5, and 11.5 km³, respectively. About 40% of this volume arrives during May snowmelt, with minimal inflow in February and March. This seasonal flow raises and lowers sea level, promoting exchange with the Barents Sea. Each year, roughly 2,000 km³ flows into the White Sea and 2,200 km³ flows out. Spring freshwater inflow lowers surface salinity in the top 5–10 meters to 23‰ in the east, 26–27‰ in the west, and 10–12‰ in Dvina Bay, while also increasing silicon and silicate content—a characteristic feature.

Storms peak in October and November. Shallow depths keep average wave height at 1 meter, occasionally reaching 3–5 meters. The sea is calm in July and August. The climate is polar to subarctic, with frequent fog and clouds. Winter winds are mostly southwestern at 4–8 m/s, bringing cold air from the south and temperatures around −15°C in February over most of the sea. The north is warmer, about −9°C, sometimes −6°C, due to Atlantic air masses. Arctic anticyclones shift winds to the northeast, bringing colder weather near −25°C. Summers are cold, cloudy, and humid, with northeastern winds and frequent rain. Average July temperatures are 8–10°C. Occasional southeastern winds from Europe can raise temperatures to 17–19°C, sometimes 30°C. Annual precipitation ranges from 282 mm in the north to 529 mm in the south.

From October–November to April–May, the sea freezes. Average January water temperatures are −1.9°C in the north, −1.3 to −1.7°C in the center, and −0.5 to −0.7°C in the bays. These differences reflect salinity variations: 24–26‰ in the center, 30.5‰ in the gorlo, and 34.0–34.5‰ toward the Barents Sea. The freezing period varies yearly, and the ice is not stationary.