The negative air temperature has prevailed in Lithuania for a while, therefore the first ice phenomena have begun to form in the rivers. When the air temperature drops below zero degrees, the cooling process of the surface water layers begins, so ice formations appear near the banks and in places where the river current is weak or almost standing. The freezing of the water creates favourable conditions for the formation of ice crystals, which later merge into blocks of a sponge structure, due to which the density of the ice decreases. First, pancake ice begins to form, and only then do these formations merge into larger ice floes. In places where the river is narrowed or makes sharp turns, near islands or artificial structures, the speed of ice floes increases, or decreases if their density on the river surface is high. In the presence of long-term negative air temperatures, this leads to the formation of a continuous ice cover.
Scientists from the LEI Laboratory of Hydrology, as part of the project “Ice-jam flood risk management in Latvian and Lithuanian regions with respect to climate change” (ICEREG), monitor river changes to improve the management of ice jam flood risks.
In visuals: floating pancake ice in the Neris River.