Yamsay Mountain is located in what is sometimes called the Eastern Cascade Mountain Range. Technically it’s the first range in the basin and range province in Oregon and California. The Medicine Lake Highlands, to the south, and Newberry Crater to the north, are other volcanoes in the range.
While geologists continue to debate the processes that formed these mountains, we’ll go with the theory that the Farallon tectonic plate slipped under the North American plate along the west coast of the United States. Initially that movement compressed the rocks of the region and effectively increased the depth of the earth’s crust in the area. As the Farallon plate dipped deeper into the earth’s mantle it released magma that flowed upward. That magma forced the crust upward several thousand feet and led to thinning of the crust. The magma broke through the crust and formed the volcanoes of the Cascade Mountains and the ranges of the Basin and Range Province. Yamsay Mountain is one of those mountains. It erupted many times layering lava upon lava to form a huge shield volcano.
After the mountain formed, the cold north slopes of the 8,196 foot peak held snow and ice creating alpine glaciers that gradually carved out what is now the Jackson Creek watershed as they crept down the mountain over thousands of years. With the explosion of Mount Mazama 7700 years ago, to form Crater Lake, Yamsay was showered with pumice and ash that still covers its flanks.
Native Americans have inhabited this area for at least 14,000 years, based upon radio-carbon evidence from Paisley Caves to the southeast of Yamsay Mountain. The Klamath Tribes gave Yamsay Mountain a special place in their belief system as the home of the creator. They named the mountain Yamsi. According to Albert Samuel Gatschet writing in The Klamath Indians of Southwestern Oregon (1890), available from the First Nation Collection at the Southern Oregon Digital Archives :
The first northern Europeans, trappers for the Hudson’s Bay Company including Finan McDonald, entered the area in 1825. That led to trade with the natives, more exploration, particularly by John C. Fremont, and the eventual arrival of settlers.
The Yamsay Mountain Trail follows the remains of a road that once led to the fire lookout on top of the mountain. The road was built in 1928 and 1929 by the Klamath Indian Agency Forestry Department. It was rebuilt in 1937. An 80-foot steel tower with a 7’X7′ steel cab on top was built immediately after the road was completed in the summer of 1929. There was a cabin on the ground that provided living space for the lookouts. Eventually the old lookout deteriorated due to winter conditions and was declared unsafe. In 1961, the Winema National Forest removed the old tower and cabin and installed a 20 foot tall wooden tower with living space on top of it. That tower was finally removed in the 1970’s when it was no longer needed. Remains of the towers and the original living quarters are still visible at the summit.
Yamsay Mountain is located about 35 miles east of Crater Lake in south-central Oregon
(42°55′50″N 121°21′39″W). The Fremont National Recreation Trail climbs Yamsay Mountain from the east and ends at the peak. Rather than that route, we used the Yamsay Mountain Trail that climbs the west side of the mountain.
The adventure starts with finding the trailhead. You will want to get a copy of the Upper Klamath Basin Recreation Map at the Chemult Ranger Station, if you are coming from the north, or the Chiloquin Ranger Station if you are coming from the south. Both Ranger Stations are on U.S. Highway 97.
Heading east from Highway 97 on the Silver Lake Road (42° 52′ 4″ N, 121° 49′ 55″W):
Note that the Jackson Creek Campground is rustic and free (campsites and vault toilets adjacent to Jackson Creek). It’s a great place to camp if you are traveling a long way to make this climb.
It may seem like it should be a fairly easy hike on an old road. However, when the road was decommissioned, a series of deep waterbars (dips and berms) were installed all along it. Highly erodible Mazama pumice forms the forest floor here. Without periodic maintenance, the road would have regularly washed out. The deep waterbars are designed to insure that water is dispersed from the trail without forming a torrent that would cause severe erosion. The deep waterbars also make it foolhardy to try driving a four-wheeled vehicle on the trail. The waterbars create a continual up and over and down process throughout the hike. It’s a bit easier coming down when you can combine your momentum and your trekking poles to launch yourself over the berms.
If that’s not enough, the trail is plagued with fallen trees. In many places it is necessary to climb over or walk around these trees. It looked to me like the trail had been opened up a few years earlier, but at the time we hiked the trail more trees had fallen. There are fallen trees across the entire area, so in many places it was necessary to weave a path around them both on and off the trail. If you are trying to set a speed record on this trail, you will need to wait until it is cleared.
When we hiked the trail (July 9, 2016) there were scattered wildflowers along the way and even more at the summit. Here is a slideshow displaying some of the flowers (and fungi) we saw:
This map shows the vicinity of Yamsay Mountain. The route to the trailhead is highlighted with red dots. The trail to the summit is highlighted with red footprints. To see more detail click the map or, for high resolution, download the PDF version (3.6MB).