East Siberian Sea runoff into the East Siberian Sea is relatively small at about 250 km/year that makes only 10% of the total runoff in all the Arctic seas of Russia. The largest contribution is from the Kolyma River at 132 km, followed by the Indigirka River at 59 km. Most runoff (90%) occurs in summer; it is concentrated near the coast, owing to the weak river currents, and therefore does not significantly affect the sea hydrology. The water exchange between the neighboring seas is as follows. The annual outflow to the Laptev Sea, Chukchi Sea and Arctic Ocean is 3,240, 6,600 and
East Siberian Sea in autumn due to the winds. It is the lowest in March–April, with the total annual fluctuations within about 70 cm. Winds bring storms with waves reaching 3–5 m in the western part whereas the eastern regions are relatively calm. The storms typically last 1–2 days in summer; they are more frequent in winter and may extend up to 3–5 days. The sea freezes over between October–November and June–July. The ice is continuous and stationary near the coast, reaching the thickness of 2 m by the end of winter; The thickness decreases from west to east. Further into the sea,