subglacial

adj.
Formed or deposited beneath a glacier.

subglacially sub'gla'cial·ly adv.

At the base of a glacier, hence subglacial channel, subglacial stream, a stream flowing in a tunnel at the bottom of an ice sheet or glacier, usually close to the edge or snout. Subglacial streams are fed by streams on the top of the glacier, which descend through ducts in the ice. These streams can flow at very high pressures, and consequently have considerable erosive power. See also esker.