The shallowness and low salinity of the sea make it vulnerable to freezing during the winter. Fast ice bands ranging from 7 km in the north to 1.5 km in the south can occur temporarily at any time from late December to mid-March. Several ships were trapped in ice in 2012 when it froze over. The ice thickness reaches in most parts of the sea and 60–80 cm in the Taganrog Bay. The ice is often unstable and piles up to the height of several metres. Before the introduction of icebreakers, navigation was halted in the winter.