Fig. 92: “Skeleton” of a glacier. In regions with extremely cold climates, as glaciers retreat, thin, and waste away, many of their deposits and associated landforms are preserved, sharply etched on the landscape. This example shows remarkably distinct multiple moraine ridges, glacial outwash plains, and moraine-dammed lakes. As the climate gradually ameliorates, such features become much less distinct and may even disappear. This is because they have ice cores, with ice forming as much as 90 percent of the entire feature.