mountrainiernps:The landscape around Mount Rainier holds many clues to the region’s past. At the hei

mountrainiernps:The landscape around Mount Rainier holds many clues to the region’s past. At the height of the last ice age some 10,000 years ago, Mount Rainier’s glaciers covered the majority of what is now the National Park, including this spot at Box Canyon. At that time, the Cowlitz-Ingraham glacier, which carved this canyon, extended over 40 miles down the valley which now holds the Cowlitz River, reaching beyond where the town of Randle now lies. The immense pressure of many cubic miles of ice eroded the long channels shown in the first image, which looks “upstream” towards the source of the glacier (note cloud-covered Mount Rainier to the left.) The glacier has since advanced and retreated past this spot several times, including as recently as 1850 during a period of cooler temperatures in the Northern Hemisphere known as the “Little Ice Age.”The influence of these past glaciers also extends to the plant communities found in this area. Water cannot easily seep into the dense volcanic rock, so it collects in these ice-carved channels, creating a variety of micro-habitats where different plant species can thrive. In the second image, russethair saxifrage and several species of moss cover the drier raised areas, while grasses, buttercups, and lilies grow in the watery channels. If you visit Box Canyon, take a close look at the rocks for additional evidence of these glaciers – in addition to the large channels shown here, you can also see tiny scratches and grooves left behind by grit and pebbles caught beneath the moving ice.__________NPS/B. Silver-Bates Photos. Descriptions: 1) A smooth rock slope with a thin layer of vegetation borders a walkway with a low wood fence. 2) Water trickles down a narrow rock channel with vegetation clustered along the channel. ~bsb/kl -- source link

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