The Dynamics of Spring Ice Drifts and Jams in the Northern Dvina and Pechora Mouths.

The dynamic type of ice drift development is found to dominate in the mouth zones of the Northern Dvina and Pechora rivers in the period of spring ice break. The ice drift is accompanied by the formation of ice jams in the mouth, the most common among them being jams of arched and wedge type. The jams are a common cause of flooding of towns and settlements in the region. The particular features of ice breaking in the mouths of northern rivers are discussed along with the regularities of ice jam formation during ice drift. The formation of jams is shown to be associated with stable retardation of ice in the sites of river channels that have specific morphological characteristics or to be caused by drifting ice mass running into solid ice fields in lower parts of river delta arms. [ABSTRACT FROM AUTHOR]