Audio
2. Hillside Road Cuts
Transcript
Mount Rainier is an active volcano formed by the accumulation of many layers of lava, volcanic debris, ash, and pumice during thousands of years of volcanism and glaciation. Some of these events, such as the Osceola Mudflow, form visible layers of different types of material in the hillside road cuts. Here’s a description of what to look for along the road from Carolyn Driedger, a hydrologist from the United States Geologic Survey:
Carolyn Driedger: “As you’re traveling up the road, especially in the lower part of the valley, you’re going to see some outcrops of very loose rock unsorted. It has big boulders set into a fine matrix and much of that is from the Osceola Mudflow, the big mudflow that formed 5600 years ago when we had an eruption of Mount Rainier... So we’re looking at this landslide from just the base of the mountain, and you’ll see as you travel that it did travel a fair ways up the valley wall... It hardened here in place and you can see it’s a very unstable slope and we get a lot of small rock falls off this slope over the years.”
Your next stop will be at a pull off with a low profile exhibit sign that is 2.3 miles from the gate. Across the road from the pull off is a rock formation that looks like dark grey columns embedded in the hillside. These columns are remnants of an old lava flow that helped form Sunrise Ridge. Stop at the pull off and play the next section of the tour
Description
Track 2 of the Sunrise Geology Audio Tour: Hillside Road Cuts
Duration
1 minute, 29 seconds
Credit
NPS
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