Ashes, Erosion and Mini-Canyons
In Washington, United States
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Before you start!! Remember to keep your feet on roadways and your hands in your pockets. Touch with your eyes and cameras only.
An $8 daily or $30 annual Northwest Forest Pass is required for each vehicle visiting this area.
During the eruption of Mount St. Helens on May 18, 1980, hot rock and ash were blasted laterally up to 17 miles, killing everything in their path. The results of this blast were confined to the local area. You will see these results along the road to the Johnston Ridge Observatory.
The vertical ash eruption lasting 9 hours rose to a height of 15 miles above the crater and drifted to the northeast. The results of this part of the blast were much more far reaching, disrupting travel and causing widespread economic loss as far to the east as western Montana. It turned daylight hours dark as the ash drifted over and fell in eastern Washington. Trace amounts of ash were detected around the world.
Small explosive eruptions of ash and rock continue to occur on a regular basis to the present time.
In areas on the mountain flanks where the thick layers of ash settled, trickles of water turned into rivulets and began to carve new channels down the mountain slopes. These rivulets turned into streams that cut even deeper into the ash, carrying some of the ash with them, giving a distinctive color to the streams.
Over the years, these streams have carved mini-canyons into the ash, exposing ash walls to view. In flatter areas, the ash carried by the streams and rivers settled, forming plugs that resulted in newly formed lakes such as Coldwater Lake and Castle Lake.
To log your find for this earthcache, you will visit two spots along the main road. Gather the information requested and send it to me in a separate e-mail BEFORE logging your find. Log your find immediately after sending the information. I will only respond to your answers if there is a problem.
1. Please log your find as soon as you send answers - don't wait for permission. Currently there are better observation locations. Coordinates will be changed in spring of 2017 after more exploration. Simply do your best to answer the questions at this time.
1. At N 46° 16.909 W 122° 11.693 (posted coordinates)
a) walk along the road to see the creek and describe what you see related to ash and erosion.
b) stand at the given coordinates and look at exposed ash on the hill next to you. Describe the color of this material.
2. At N 46° 16.978 W 122° 11.880 (site 2 coordinates)
a) describe evidences of erosion you observe at this site.
b) tell what is stated on one of the signs at the given coordinates.
(No hints available.)
Last Updated: on 4/24/2017 3:31:39 PM Pacific Daylight Time (10:31 PM GMT)
Coordinates are in the WGS84 datum