 A series of photos shows the Grinnel Glacier in 1938, 1981, 1998 and 2009. In 1938, the lake beneath the glacier was completely frozen. In 1981, about one-third of the lake was thawed. In 1998, two-thirds of the lake was thawed. In 2009, it was covered with chunks of ice, but otherwise it was completely thawed. At the same time, the glacier itself has steadily receded.