Mount Adams is a stratovolcano located in the Cascade Range of Washington, United States. Standing at feet, it is the second-highest mountain in Washington and a prominent feature within the Cascade Volcanic Arc, which formed as a result of the subduction of the Juan de Fuca Plate beneath the North American Plate. Adams is near two more-frequently erupting neighbors, Mount St Helens and Mount Rainier. It has twelve named glaciers descending its slopes.
Geologically, Mount Adams first formed in the Pleistocene. Its construction involved multiple eruptive phases, the first around 500,000 years ago, followed by the development of the modern cone around 10,000 years ago. The last known lava flow was approximately 1,000 years ago. The volcano has the potential for future hazards, including lahars, pyroclastic flows, and ashfall. Its deeply eroded flanks drain into major regional rivers like the Cispus, Klickitat and Lewis Rivers.
The mountain is home to diverse ecological zones, ranging from dense lower-elevation forests dominated by Douglas fir and western hemlock on its western slopes to drier ponderosa pine forests on its eastern slopes. These ecosystems support a rich array of flora and fauna, including large mammals like Roosevelt elk and black-tailed deer, as well as a variety of bird species and abundant wildflowers in the summer months.
The Yakama Nation, who reside on the eastern slopes, incorporated the mountain into their legends before the Europeans arrived. European-American explorers first documented the peak in the early to mid-19th century. The mountain was officially named after President John Adams in 1853, although the assignment of the name to the peak was due to mapmaker confusion. The first recorded ascent was made in 1854. Today, a significant portion of Adams is designated as the Mount Adams Wilderness.
Mount Adams is a popular destination for outdoor enthusiasts, offering a range of activities. Mountaineering is prominent, with the non-technical South Spur being the easiest climbing route to the summit. Hiking, backpacking, and camping are popular throughout the warmer months. The Pacific Crest Trail traverses the western flank of the mountain. In winter, visitors enjoy cross-country skiing and snowmobiling.
Name There are several names for the mountain in the various Indigenous languages in its vicinity. In the Sahaptin language to the east, it is called . The word can refer to any snow-covered mountain, but the "main" is Mount Adams. This name has been anglicized variously as Paton, Pahto, Pahtoo, Pahtoe, and Pat-to. It is also nicknamed in the Yakama dialect of Sahaptin. This name means "golden eagle" and references the shape of a golden eagle appearing in the snowcap.
In the Cowlitz language to the northwest, it is called . Additionally, there is the name , which is loaned from the Sahaptin name.
To the south is the Upper Chinook language. An early-20th century mountaineer, William Denison Lyman recorded a Wasco-dialect name for the mountain, "Kakon," which he stated can refer to any high mountain.
One Oregon history magazine stated that the Native American name for the mountain was "Klick-i-lat" Lyman sometimes called it "Klickitat" in his writings. The name "Klickitat" originally referred to a permanent village opposite what is today Lyle, Washington. This spot is called in Lower Chinook, in Sahaptin (borrowed from Lower Chinook), and in Upper Chinook, the language of the Wasco people there. The Klickitat people who bear the name call themselves and had villages on the Lewis, White Salmon, and Klickitat rivers.
Its English name, Adams, is named after John Adams, the second president of the United States. In the 1830s, Hall J. Kelley led a campaign to rename the Cascade Range as the President's Range and 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 was instead designated by Kelley to be renamed after John Adams and St. Helens was to be renamed after George Washington. In a mistake or deliberate change by mapmaker and proponent of the Kelley plan, Thomas J. Farnham, the names for Hood and St. Helens were interchanged. And, likely because of the confusion about which mountain was St. Helens, he placed the "Mount Adams" name north of Mount Hood and about east of Mount St. Helens. Although unknown to Kelley, there was in fact a large mountain there to receive the name. Since the mountain had no official name at the time, Kelley's name stuck, although the rest of his plan failed. The name was not official until 1853, when the Pacific Railroad Surveys, under the direction of Washington Territory governor Isaac I. Stevens, determined its location, described the surrounding countryside, and placed the name on the map.
Geography
General
Mount Adams stands east of Mount St. Helens and about south of Mount Rainier. It is north of the Columbia River and north of Mount Hood in Oregon. The nearest major cities are Yakima, to the northeast, and the Portland metropolitan area, to the southwest. Between half and two thirds of Adams is within the Mount Adams Wilderness of the Gifford Pinchot National Forest. The remaining area is within the Mount Adams Recreation Area of the Yakama Indian Reservation. While many of the volcanic peaks in Oregon are located on the Cascade Crest, Adams is the only active volcano in Washington to be so. It is farther east than all the rest of Washington's volcanoes except Glacier Peak.
Adams is one of the long-lived volcanoes in the Cascade Range, with minor activity beginning 900,000 years ago and major cone building activity beginning 520,000 years ago. The whole mountain has been completely eroded by glaciers to an elevation of twice during its lifetime. The current cone was built during the most recent major eruptive period 40,000–10,000 years ago.
Standing at , Adams towers about over the surrounding countryside. It is the second-highest mountain in Washington and third-highest in the Cascade Range. Because of the way it developed, it is the largest stratovolcano in Washington and second-largest in the Cascades, behind only Mount Shasta. Its large size is reflected in its -diameter base, which has a prominent north–south trending axis.
Adams is the source of the headwaters for two major rivers, the Lewis River and White Salmon River. The streams on the north and east side of Adams feed the Cispus and Klickitat Rivers, respectively.
Mount Adams is the second-most isolated, in terms of access, stratovolcano in Washington; Glacier Peak is the most isolated. Only two major highways pass close to it. Highway 12 passes about to the north of Adams through the Cascades. Highway 141 comes within of Adams as it follows the White Salmon River valley up from the Columbia River to the small town of Trout Lake. From either highway, travelers have to use Forest Service roads to get closer to the mountain. The main access roads, FR 23, FR 82, FR 80, and FR 21, are paved for part of their length. Almost all other roads are gravel or dirt, with varying degrees of maintenance. Access to the Mount Adams Recreation Area is by way of FR 82, which becomes BIA 285 at the Yakama reservation boundary. BIA 285 is known to be extremely rough and often suitable only for trucks or high-clearance vehicles.
The mountain's size and distance from major cities, and the tendency of some people to forget or ignore Mount Adams, has led some people to call this volcano "The Forgotten Giant of Washington".
On a clear day from the summit, other visible volcanoes in the Cascade Range include: Mount Rainier, Mount Baker, and Glacier Peak to the north, as well as Mount St. Helens to the west, all in Washington; and Mount Hood, Mount Jefferson, and the Three Sisters, all to the south in Oregon.
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, Pikers Peak, rises on the south side of the nearly half-mile (800 m) wide summit area. The true summit is about higher on the gently sloping north side. A small lava and scoria cone marks the highest point. Suksdorf Ridge is a long buttress descending from the false summit to an elevation of . This structure was built by repeated lava flows in the late Pleistocene. The Pinnacle forms the northwest false summit and was created by erosion from the Adams and White Salmon glaciers. On the east side, The Castle is a low prominence at the top of Battlement Ridge. The summit crater is filled with snow and is open on its west rim.
Flank terrain features Prominent ridges descend from the mountain on all sides. On the north side, the aptly named North Cleaver comes down from a point below the summit ice cap heading almost due north. The Northwest Ridge and West Ridge descend from the Pinnacle, to the northwest and west, respectively. Stagman Ridge descends west-southwest from a point about halfway up the west side and turns more southwest at about . South of Stagman Ridge lies Crofton Ridge. Crofton gradually becomes very broad as it descends southwesterly. MacDonald Ridge, on the south side, starts below the lower end of Suksdorf Ridge and descends in a southerly direction.
Three prominent ridges descend from the east side of the mountain. The Ridge of Wonders is farthest south and ends at an area away from the mountain called The Island. Battlement Ridge is very rugged and descends from high on the mountain. The farthest ridge north on the east side, Victory Ridge, descends from a lower elevation on the mountain than Battlement Ridge beneath the precipitous Roosevelt Cliff. Lava Ridge, starting at about the same location as the North Cleaver, descends slightly east of north.
Several rock prominences exist on the lower flanks of Adams. The Spearhead is an abrupt rocky prominence near the bottom of Battlement Ridge. Burnt Rock, The Hump, and The Bumper are three smaller rocky prominences at or below the tree line on the west side.
Surrounding area
Mount Adams is surrounded by a variety of other volcanic features and volcanoes. It stands near the center of a north–south trending volcanic field that is about wide and long, from just south of the Goat Rocks to Guler Mountain, the vent farthest south in the field. This field includes over 120 vents; about 25 of these are considered flank volcanoes of Mount Adams. 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 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 above its lava plain.
Lavas from its base flowed into the Cispus Valley where they were later modified by glaciers. At the 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 last ice age.
Several relatively young obvious lava flows exist in the area around Adams. Most of these flows are on the north side of the mountain and include the flow in the Mutton Creek area, Devils Garden, the Takh Takh Meadows Flow, and the much larger Muddy Fork Lava Flow to the north of Devils Garden. Only one obvious flow appears on the south slopes of Adams, the A. G. Aiken Lava Bed. Other smaller flows exist in various locations around the mountain as well.
The many other vents and volcanoes encompassed by the Mount Adams field include Glaciate Butte and Red Butte on the north, King Mountain, Meadow Butte, Quigley Butte, and Smith Butte on the south, with others interspersed throughout.