A VANISHING LANDSCAPE: CURRENT TRENDS FOR THE GLACIERS OF MOUNT RAINIER NATIONAL PARK, WASHINGTON, USA

Mount Rainier is the most glaciated volcano in the Cascade Range of the western United States and has more glacial ice on its edifice than all other volcanoes in the Cascade Range combined. Measuring rates of glacial ice loss during warming climates are critical to understanding the future impacts to riparian areas downslope of the glaciers, sediment production to braided rivers, aquatic impacts due to increasing stream temperatures, and many other important areas for park resource management. Glacial area has been delineated many times in the last century; most importantly in 1896, 1913, 1971, 1994, 2009, and, most recently, in 2015. Each of these extents represents a snapshot of the surface area of the volcano occupied by glacial ice during those years and provides an opportunity to visualize the health of the glaciers in the park over time. Using aerially derived Structure from Motion (SfM) data acquired in September 2021, as well as other satellite and aerial imagery, glacier area for each of the 29 named glacial features is updated for Mount Rainier and presented here. From these source data, we have mapped not only the extent of ice but estimate the volume of ice from methods developed by other researchers in the past. Overall, our data shows a continuation of gradual yet accelerating loss of glacial ice at Mount Rainier, resulting in significant changes in regional ice volume over the last century. Regional climate change is affecting all glacial features at Mount Rainier, but mostly those smaller cirque glaciers and discontinuous glaciers on the south aspect of the volcano.