With the end of the Little Ice Age these glaciers began a slow retreat. After 1920 the rate of shrinkage sped up. In the 100 years since the height of the Little Ice Age and 1950, Mount Rainier lost about one-quarter its glaciers. After 1950 until the 1980s the larger glaciers made small advances. Since the 1980s, many glaciers have been thinning and retreating.