<P> The size of glaciers on Mount Rainier has fluctuated significantly in the past . For example, during the last ice age, from about 25,000 to about 15,000 years ago, glaciers covered most of the area now within the boundaries of Mount Rainier National Park and extended to the perimeter of the present Puget Sound Basin . </P> <P> Between the 14th century and 1850, many of the glaciers on Mount Rainier advanced to their farthest extent downvalley since the last ice age . Many advances of this sort occurred worldwide during this time period known to geologists as the Little Ice Age . During the Little Ice Age, the Nisqually Glacier advanced to a position 650 to 800 ft (200 to 240 m) downvalley from the site of the Glacier Bridge, Tahoma and South Tahoma Glaciers merged at the base of Glacier Island, and the terminus of Emmons Glacier reached within 1.2 mi (1.9 km) of the White River Campground . </P> <P> Retreat of the Little Ice Age glaciers was slow until about 1920 when retreat became more rapid . Between the height of the Little Ice Age and 1950, Mount Rainier's glaciers lost about one - quarter of their length . Beginning in 1950 and continuing through the early 1980s, however, many of the major glaciers advanced in response to relatively cooler temperatures of the mid-century . The Carbon, Cowlitz, Emmons, and Nisqually Glaciers advanced during the late 1970s and early 1980s as a result of high snowfalls during the 1960s and 1970s . Since the early - 1980s, however, many glaciers have been thinning and retreating and some advances have slowed . </P> <P> The glaciers on Mount Rainier can generate mudflows, through glacial outburst floods not associated with any eruption . The South Tahoma Glacier generated 30 floods in the 1980s and early 1990s, and again in August, 2015 . </P>

Which of the following is an accurate characterization of mt. rainier