The glacier has retreated since the end of the Little Ice Age in the mid-19th century. During the mid-20th Century, the glacier split into two smaller glaciers occupying the high cirques of Mount Lyell.
Since 1883, the glacier area has retreated up to 70 percent.[4] Another glacier, the Maclure Glacier on nearby Mount Maclure, has also retreated significantly.
According to a study in 2013, today the Lyell is no longer a glacier, having lost any movement and thus it should be considered an ice field.[5][6]
^Muir, John, 1873. On Actual Glaciers in California. American Journal of Science and Arts, v:69-71
^Mount Lyell, CA (Map). TopoQwest (United States Geological Survey Maps). Retrieved September 30, 2012.
^"Twentieth Century Glacier Change in the Sierra Nevada, California". Hassan Basagic. May 14, 2005. Archived from the original on September 6, 2006. Retrieved January 11, 2007.
^"California's Vanishing Glaciers: A Defining Moment | KQED". Kqed.
^Gilbreath, Aaron (April 12, 2019). "What the Death of a Glacier Means for Us". Longreads.