Today we see a spectacular maze of jagged peaks and spires, and broad, U-shaped valleys carved out by glacial action. At least three major glacial advances and retreats sent great masses of ice slowly but meticulously creeping down the mountains, carving and grinding out the valleys we see today. The last major advance of glaciers was during a period of geologic time called the Pleistocene, or Great Ice Age. During the Pleistocene, the overall temperature of the world was much cooler than it is today. Significant snow packs built up, creating great ice sheets that at one time covered over 50% of Alaska. About 12,000 years ago, these great ice sheets and glaciers retreated as the world's climate experienced a warming trend. The awesome and spectacular landscapes we see throughout the park and preserve today are remnants of this period.
Pleistocene, last major advance of glaciers was during a period of geologic time called the Pleistocene, or Great Ice Age.
Pleistocene, last major advance of glaciers was during a period of geologic time called the Pleistocene, or Great Ice Age.