"bouncing back" of the mantle (and the crust atop it) following the removal of weight. The weight of thousands of feet of glacial ice would have depressed the plastic magma of the mantle. When the ice weight was removed, the magma rebounds.

a geological concept that explains how the crust of the earth can rise up after being pushed down by the weight of glaciers. Evidence of isostatic rebound is common along shorelines in glaciated regions around the world.

The upward movement of the Earth's crust following isostatic depression.

The return to equilibrium after some change in the weight of the crust; i.e. ice sheets.

the adjustment of the lithosphere of the earth to maintain equilibrium among units of varying mass and density. Excess mass above is bal-anced by a deficit of density below, and vice versa . Weight added onto the earth's surface depresses the lithosphere slowly, and weight removed permits the litho-sphere to rise slowly, but usually not to the same elevation it had before it was de-pressed.

When the land rises after a weight is removed; on the Kenai this is happening since the glaciers have receded at the end of the Pleistocene.