General term for a glacial drainage channel cut by water during glaciation, and normally including three varieties: (a) channels cut by water escaping from a glacially impounded lake (see overflow channel); (b) channels cut by meltwater released from a decaying glacier (see meltwater channel); and (c) channels cut by a stream deflected by an advancing glacier. Impressive examples were developed in central Europe (the Urstromtäler of northern Germany) when the Scandinavian ice sheet diverted streams flowing north from the southern highlands.