river ice

River ice formation is more complex than in lakes due to water velocity and turbulence. Rivers cool uniformly, and supercooling can occur, where water temperature drops below freezing without ice forming. Introduction of ice particles triggers nucleation, forming "frazil ice," which are small ice disks. These particles can accumulate, forming anchor ice on the riverbed or hanging dams in deeper rivers.

Ice jams occur when moving ice blocks the river, often where the slope changes or ice meets an intact cover. This can cause localized flooding. Spring breakup jams, with larger ice quantities, are typically more destructive than freeze-up jams. Methods to manage ice include icebreakers, dusting ice to increase solar absorption, trenching, and explosives for jams. Ice-retention structures and controlled water releases are also used.123456