Pleistocene glaciers periodically covered the region and sculpted the rugged beauty of the Teton Range. Topographic features such as glacial outwash plains, moraines, kettles, U-shaped canyons, striated and polished bedrock, and river terraces reflect glacial activity. Today, about a dozen named glaciers, of which Teton Glacier is the largest, cling to the mountain slopes, sheltered in high-altitude, northeastfacing cirques. These glaciers are not remnants of the Pleistocene Ice Age but formed during the Little Ice Age, a cold period from roughly 1400–1850. If the climate continues to change, these glaciers will likely disappear.