Each move in Mount Rainier National Park has seemed like a new park, the mountain still dominates the view, but the environment changes dramatically. Cougar Rock was a Lodgepole and Ponderosa Forest, Paradise was on open bowl of vast snowfields and meadows, Ohanapecosh was a hidden forest with moss draped trees and that spectacular river, and now White River campground is perched on the edge of a heavily silted glaciel river with views up the Emmons Moraine to the massive glaciers of Mount Rainier. [Moraine: A Moraine is the debris field of gravel, sand, and rocks left by a retreating glacier – a glacier grinds up rocks into gravel and sand and carries them along as it grows, when it recedes it drops the gravel behind it. The Moraine can be hundreds of feet thick, depending on the size of the original glacier.] Emmons Glacier is over 200 feet thick and at this time 3 – 4 miles long.
Honestly, I expected the glaciers, especially after seeing them high on the mountain at Paradise, to be ice blue-white and shiny with new snow. Here, seeing the terminus of the Emmons glacier I was a bit taken aback by how dirty it is. Emmons Glacier, like most of the glaciers in the world, is currently receding. The glacier is covered with the glacial debris it has collected for many years and is now exposed by the melting ice. In the above picture we see the terminal wall at the foot of the glacier. You can see the blue of the ice showing through the gravel. At the bottom the White River flows out of an ice cave.
Here’s a closer view of the ice cave at the foot of Emmons Glacier. Glaciers have two distinct zones. Lower on the glacier is the ablation zone, as we see here, where the terminus of the glacier is melting and dropping it’s load of glacial debris (rocks, gravel, and sand) that it has scoured off the mountain.
Higher up on the mountain, as seen in the above picture, is the accretion zone where new snow is being compressed into ice feeding the glacier as it roars (in geological time that is) down the mountain. Put simply, if the accretion rate exceeds the ablation rate the glacier is growing, if the ablation rate exceeds the accretion rate, the glacier is receding. Recession is currently the case with Emmons. Mount Rainier has more glaciation than would normally be expected of a 14,000 foot mountain for two reasons. One, it has a lot of moisture, from the nearby Pacific Ocean, to work with, causing huge snowfalls each winter, sometimes in excess of 1,000 inches. Two, it is so big compared to its surroundings that it creates a more severe weather pattern than would be expected and cold mountain temperatures aid in the creation of the glaciers. Mount Rainier has over 20 glaciers of varying size, most of which are still active (ie, actively acrreting even though some may at present be having a net loss of volume. There are 2 inactive glaciers, basically huge chunks of ice slowly melting away. My guess is that glaciers become inactive when larger glaciers above it have usurped it’s source of water thereby starving its accretion zone. Ohanapecosh is an example of an inactive glacier and the clearness of the water we saw at Ohanapecosh is evidence of this. Rivers from active glaciers are heavily silted.
The hike to view the Emmons Glacier took us out across the Inter Fork River and up onto the moraine (see arrow above). That’s Little Tahoma Peak (11138 ft.) in the center of the picture.
The White River Valley, looking up the moraine toward Emmons Glacier and Little Tahoma Peak. You can see the gravel covered ablation zone in the center of the picture, and the ice and snow covered accretion zone above curving to the right up onto the mountain.
The Moraine Trail skirts along the eroded edge of the Moraine (arrow). The White River has carved away the center of the Moraine. At one time the glacier would have come all the way down to where Cheryl is standing to take this picture.