"Hubbard Glacier is the largest tidewater glacier on the North American continent. It has been thickening and advancing toward the Gulf of Alaska since it was first mapped by the International Boundary Commission in 1895 (Davidson, 1903). This is in stark contrast with most glaciers, which have thinned and retreated during the last century. This atypical behavior is an important example of the calving glacier cycle in which glacier advance and retreat is controlled more by the mechanics of terminus calving than by climate fluctuations. If Hubbard Glacier continues to advance, it will close the seaward entrance of Russell Fjord and create the largest glacier-dammed lake on the North American continent in historic times."