Glacier National Park contains one of the most dramatic mountain landscapes in the United States, outside of Alaska. The glacier part of the Park is now an anomaly. All of the glaciers are rapidly melting and are estimated to be gone in the next several decades. Back in 1850, it is estimated that there were approximately 150 glaciers, by 2010, the number had dropped to 25 glaciers larger than 25 acres. See the U.S. Geologic Survey, "Retreat of Glaciers in Glacier National Park" Quoting from the USGS article:
While the glaciers that carved GNP’s majestic peaks were part of a glaciation that ended about 12,000 years ago, current glaciers are considered geologically new, having formed about ~7,000 thousand years ago. These glaciers grew substantially during the Little Ice Age (LIA) that began around 1400 A.D and reached their maximum size at the end of the LIA around A.D.1850. Their maximum sizes can be inferred from the mounds of rock and soil left behind by glaciers, known as moraines (Key, 2002), which provide a scientific baseline for comparison to current glacial extent.It would be simplistic to blame the loss of the glaciers on "global warming" but there is no doubt from the climate records that the average temperature in the area of the glaciers is rising. This is a highly politicized and controversial topic, but whether or not you believe in global warming, you only have to go to Glacier National Park to the see the effects on one small area of the world.