Mount Adams (12,276 feet, 3741.7 meters) is a stratovolcano in the Cascade Range and the second highest mountain in the Pacific Northwest of the United States (Mount Rainier is the tallest). Adams is located in a remote wilderness approximately 35 miles (~35 km) east of Mount Saint Helens. The Mount Adams Wilderness only comprises the upper part of the volcano's cone. Adams' asymmetrical and broad body raises a mile and a half (2.4 km) above the Cascade crest and its nearly flat summit looks as if the volcano was decapitated (which in fact it has not).

Table of contents
1 History
2 Glaciers
3 Geology
4 Summit area
5 Area around Adams
6 Reference

History

Native Americans in the area have created a detailed legend concerning the three smoking mountains that guard the Columbia River. According to their Bridge of the Gods tale, Wyeast (Mount Hood) and Pahto (Mount Adams; also called Paddo or Klickitat by natives) were the sons of Great Spirit. The brothers both competed for the love of the beautiful La-wa-la-clough (Mount Saint Helens). When La-wa-la-clough chose Pahto, Wyeast struck his brother so hard that Pahto's head was flattened and Wyeast took La-wa-la-clough from him (thus attempting to explain Adams' squat appearance). However other versions of the story state that losing La-wa-la-clough caused Pahto such grief that he dropped his head in shame.

In 1805 the Lewis and Clark Expedition recorded seeing the mountain but they misidentified it as previously discovered and named Mt. St. Helens. This is the earliest recorded sighting of the volcano by whites.

Between 1830 to 1834 a man named Hall J. Kelley led a campaign to rename the Cascade Range to the President's Range and also to rename each major Cascade mountain after a former President of the United States. Mount Adams was not known to Kelley and was thus not in his plan. Mount Hood, in fact, was designated by Kelley to be renamed after President John Adams but a mistake by a mapmaker placed the Mount Adams name north of Mt. Hood and about 40 miles (~60 km) east of Mt. St. Helens. By sheer coincidence there was in fact a large mountain there to receive the name. Since the mountain had no official name at the time the name stuck in spite of the fact that Kelley's renaming plan failed.

In 1901 local settler and mountaineer C. E. Rusk led noted glaciologist Harry Reid to Adams' remote location. Reid conducted the first systematic study of the volcano and also named its largest glaciers. Eighty years later the first official study of Adams by the USGS was carried out by survey geologists Wes Hildreth and Judy Fierstein. They concentrated their work on the volcanology of the mountain and the potential of the area to support geothermal power. Much of our knowledge of Adams comes from their survey work.

In 1929 and 1931 a man named Wade Dean filed mining claims to the sulfur on Adams' 210 acre summit plateau. After building a horse and mule trail they moved a diamond-tipped drilling machine to the summit area and proceded to drill test pits. Although they did find sulfur sludge, the amount and quality of the ore was never good enough to make the venture profitable and the project was abandoned in 1959. Adams is the only High Cascade volcano to have its summit exploited by commercial miners.

Glaciers

Ice (mostly in the form of glaciers) covers about 6.2 square miles of the mountain's upper cone and is fed by ample snow and rainfall every year. Water peculates through the very porous interior of the main cone and exits near the volcano's base as springs.

Glaciers cover a total of 2.5% of Adams' surface but during the last Ice Age about 90 % of the mountain had glaciers on it. Most of the largest extant glaciers (including the Adams, Klickitat, Lyman, Salmon, and White ) originate from Adams' summit ice cap. On the northwest face of the mountain is Adams Glacier, which cascades down a steep channel in a series of ice falls before spreading out and terminating at around 7000 feet (~2100 meters) elevation. At the head of the Klickitat Glacier on the volcano's eastern flank, a mile-wide cirque (second in size among the Cascades only to Carbon Glacier on Mount Rainier) is fed by two smaller glaciers from the summit ice cap and terminates around 6000 feet (~1800 meters).

Geology

Main article: Geology of Mount Adams

Adams is made of several overlapping cones that together form an 18 mile (29 km) diameter base which is elongated in a north-south direction and covers an area of 250 square miles. The volcano has a volume of 85 cubic miles placing it second only to Mount Shasta in that category among the Cascade stratovolcnoes.

Summit area

Contrary to legend, the flatness of Adams' current summit area is not due to the loss of the volcano's peak. Instead it was formed as a result of cone-building eruptions from separated vents. A false summit raises 11,500 feet (3505 meters) on the south side of the nearly half-mile (~900 meter) summit area. The true summit is about 800 feet (~240 meters) higher on the gently slopping north end (a small lava cone marks the highest point). Suksdorf Ridge is a long buttress trending from the false summit down to an elevation of 8000 feet (~2440 meters). This structure was built by repeated lava flows in the late Pleistocene. The Pinacle forms the northwest false summit and was created by erosion from Adams and White Glaciers. The summit crater is filled with snow and is open on its west rim.

Area around Adams

Mount Adams is surrounded by a variety of other volcanic features and volcanos.
  • The largest flank volcano is a basaltic shield volcano on Adams east base called Goat Butte. This structure is at least 150,000 years old.
  • Little Mount Adams (450 feet, 137 meters) is a symmetrical cinder cone on top of the Ridge of Wonders on Adams' southeast flank.
  • Potato Hill is a cinder cone on Adams' north side that was created in the late Pleistocene and stands 800 feet (~240 meters) above its lava plain. Lavas from its base flowed into the Cispus Valley where they were later modified by glaciers.
  • At the 7500 foot (~2285 meter) level on Adams' south flank is South Butte. The lavas associated with this structure are all younger than Suksdorf Ridge but were emplaced before the end of the Ice Age.
  • Located a few miles north of Adams is Goat Rocks; the heavily eroded ruins of a stratovolcano that is much older than Adams. Unlike Adams, the Goat Rocks Volcano was periodically explosive and deposited ash 2.5 million years ago that later solidified into 2100 foot (640 meter) thick tuff layers.

Reference

  • Fire Mountains of the West: The Cascade and Mono Lake Volcanoes, Stephen L. Harris, (Mountain Press Publishing Company, Missoula; 1988) ISBN 0-87842-220-X