What is so special about the Cascade-Siskiyou National Monument?

This national monument spans the border between Oregon (Jackson County) and California (Siskiyou County) immediately east of the I-5 freeway. It was first established in 2000 by President Bill Clinton and expanded in January 2017 by President Obama as one of his last actions before leaving office. The monument is managed by the Bureau of Land Management (BLM) from the local Medford Oregon office. It is an important time to learn more about the monument because it is one of the four that Interior Secretary Zinke (Trump administration) has proposed to shrink. 

Several weekends ago, we hiked to Hobart Bluff in the monument with Mike and Chris from the San Francisco Bay Area. This view (with Jay and Mike) is to the northwest, parallel to the Bear Creek arm of the Rogue Valley, with Emigrant Lake in the near part of the valley and the buildings of Ashland just beyond the lakes. To the west of the valley (left side of photo) are the Klamath Mountains that consist of old Paleozoic and Mesozoic, mostly oceanic, rocks that were added to the continent many tens of millions of years ago. To the east of the valley (right side of photo) are the mountains that make up the Western Cascades—the now-eroded volcanoes that were active from about 40–15 million years ago. The currently active volcanoes are located just east of the Western Cascades; although they didn’t show up well in photographs, Mt. McLoughlin volcano was visible to the east and Mt. Shasta volcano was visible to the south.

So why was this area declared a national monument by President Clinton in the first place? Turns out this monument was the first to be recognized solely because of a desire to preserve its incredible biodiversity. In recognition of this biodiversity, the region has also been designated as an Area of Global Botanical Significance and proposed as a World Heritage Site and UNESCO Biosphere Reserve. 

And what is the cause of all this biodiversity, you may ask? Well, it’s all about the geology, of course! This location is at the intersection of the Cascade, Klamath and Siskiyou mountain ranges, with additional climatic influences from the Basin and Range province to the east (starting at Klamath Lake) and the Pacific coast to the west. These rugged mountain ranges are characterized by a complex suite of rock types that creates the various soil types, topographic changes, and micro-climates that produce so many diverse ecological niches. David Rains Wallace’s 1983 book about the natural history of the region (biological and geological), entitled “The Klamath Knot”, produced a visual way (a knot) to think about this complexity.

Clearly, there are many good reasons for preserving the natural environment of this region. As it is, there remain many private holdings within the monument, and the law allows for recreational activities such as hunting and fishing. In fact, our hike was curtailed by gun shots as we attempted to continue south to Soda Mountain. Only very limited commercial interests are likely to benefit from the monument’s shrinkage and it is my hope that the monument will remain at its current size so that more of the public can enjoy its bounty and beauty.

For more information :

—BLM site with photos and useful information: https://www.blm.gov/programs/national-conservation-lands/national-monuments/oregon-washington/cascade-siskiyou

—Site of Friends of the Cascade-Siskiyou National Monument, a group that organizes hikes and other activities in the monument and strives to protect it: http://www.cascadesiskiyou.org/

—World Wildlife Fund’s site about the area’s global significance: https://www.worldwildlife.org/ecoregions/na0516

—Wikipedia site about “The Klamath Knot”: https://en.m.wikipedia.org/wiki/The_Klamath_Knot


Human interactions with the Lava Beds landscape

The Modoc group of Native Americans have lived in the region that is now the Lava Beds National Monument for thousands of years. They left little imprint on the land, but they did leave some rock art that is interesting to examine. Two caves—Big Painted Cave and Symbol Bridge Cave—contain pictographs that are painted onto the rocks with a charcoal-based substance. The photo below, taken by Jay, is in Symbol Bridge Cave. Archeologists don’t know what the geometric symbols mean, but they do know the symbols are not writing. It’s fun to imagine what these early people were expressing when they did their art. The age of the paintings is also uncertain, but they were probably done sometime over the past few thousand years. It’s intriguing to think about how these people would have responded to the frequent eruptions of lava, and if any of the symbols relate to those natural events. The area is still active and new volcanic flows can be expected in the not-too-distant future.

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Another style of art is the petroglyphs visible at Petroglyph Point, an outlier of the National Monument on the eastern edge of Tule Lake near the town of Tulelake. This type of art is carved or pecked into the rock, which at this location is an ash-flow tuff (pyroclastic flow that erupted explosively from more silica-rich magma) that is older than the basalt in the rest of Lava Beds National Monument. The photo below, taken by Jay, shows some of the great variety of images that are displayed along what was the edge of Tule lake when it was much larger, before it was drained for agriculture. There are more than 5,000 individual carvings, making this one of the most extensive representations of Native American rock art in California. These carvings could only have been done during dry times when the lake was lower—although it is even lower now because of human activities. One estimate is that the carvings are between 1500 and 400 years old.


Unfortunately, as in other parts of the Americas, the native people were treated poorly after white settlers arrived and demanded that the Modoc people be removed to a reservation. The Modoc War occurred from 1872 to 1873, when the Modocs made a last-ditch effort to return to their native lands after being expelled to the reservations of other native groups with whom they had conflicts. Within Lava Beds National Monument is Captain Jack’s Stronghold, a natural lava fortress where a young Modoc leader named Kientpoos (called “Captain Jack” by the settlers) and several hundred of his people held off U.S. military soldiers for months. The Modoc people ultimately lost this war, of course, and it is only in recent years that some of them have returned to try to reestablish their spiritual bonds to the land of their ancestors. This “totem” in the stronghold contains various momentos of recent visitors to the area.

Note the broad, low-relief shape of the shield-type Medicine Lake volcano in the distance (view looking south). The remaining bit of snow is on top of Glass Mountain, on the eastern flank of the volcano.


Another group of people were more recently mistreated in this area, when after the attack of Pearl Harbor during WWII the U.S. government demanded that Japanese-Americans be relocated to internment camps, one of which was located on the eastern edge of Tule Lake. This area is now a National Historic Landmark and visitors can learn more about it on a tour with a park service guide. The government sold off the barrack-style buildings long ago, but the map in the guide’s hands shows the hundreds of housing units that were built close together and inadequately constructed for the weather extremes in the region. This is yet another very sad tale of U.S. discrimination—Japanese people were forced to leave their businesses and most of their possessions behind and were incarcerated with poor living conditions until the war was over. In our group was a woman from the San Francisco Peninsula whose father and mother were both interned in these camps when they were young people and U.S. citizens.


The Lava Beds National Monument and the Tule Lake Segregation Center National Historic Landmark are two national sites that deserve more visits from the public.

Lava lava everywhere—Lava Beds National Monument, NW California

I’ve said there are just two Cascade Range volcanoes in California—Mt. Lassen and Mt. Shasta. But there is a third called Medicine Lake Volcano, as shown on the map below (from https://en.wikipedia.org/wiki/Cascade_Volcanoes). Lava Beds National Monument is located just north of the volcano, where numerous flows have completely covered the landscape during the past 500,000 years.


Because it is a shield volcano, like the volcanoes in Hawaii, the Medicine Lake volcano is not as obvious in the landscape as the classic-shaped composite (or strata) cones like Shasta and Lassen . Shield volcanoes have a low profile because the lava forms from silica-poor magma (mostly basalt) that is more fluid and can’t hold up steep-sided cones like their composite cousins with more sticky, thick eruptive materials formed from magma richer in silica. The photo below (view to SW from Schonchin Butte) shows the western half of the Medicine Lake volcano with many cinder cones of various ages on its flank. One is obviously very young because it lacks any vegetation. In contrast, Mt. Shasta in the background (right side of photo) has steeper slopes and an overall higher elevation. Although Medicine Lake volcano may not look as impressive, by volume it is the largest Cascade Range volcano!

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Why is the Medicine Lake volcano different than the other Cascade Range volcanoes? Because it is at the intersection of the Cascade Ranges and the Basin and Range province, where normal faults are causing Earth’s crust to be pulled apart and where avenues are provided for magma to travel more directly from deeper depths (the mantle), without as much mixing with the silica-rich continental crust. The photo below (view to the NW from Schonchin Butte; taken by Jay Ach) shows Gillem bluff, which is a fault block that has been uplifted and tilted westward (left side of photo) relative to the down-dropped block to the east that is occupied by Tule Lake and agricultural fields. The dark area in front of Gillem bluff is the Devil’s Homestead flow that erupted about 10,000 years ago.

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The Medicine Lake volcano has had eruptions of more silica-rich magmas—for example, Glass Mountain on the eastern flank, where a ~950-year-old eruption produced extensive obsidian flows. But at Lava Beds, most of the lavas are basalt that form a wide variety of small cones and flow types. Just like in Hawaii, visitors can see rope-like “pahoehoe” lava (photo below) that forms when the lava is very hot and flowing freely.


When the lava is cooler and flowing more slowly, it forms “aa” lava. In the photo below, Jay is saying “ah-ah” as he tries to walk across the very rough Devil’s Homestead flow.


Most of the flows in Lava Beds emanated from Mammoth Crater, an impressive hole-in-the-ground at the southern end of the park, where the Big Nasty Trail provides an interesting 2-mile-long excursion across lava that is really not all that nasty.


A map in the Visitors Center, located near the Mushpot Cave, shows how lava from Mammoth Crater has flowed north across the landscape. It also shows where the most popular caves are located.


In addition to cinder cones, there are “spatter cones”. It is fun to imagine blobs of hot lava being spewed from a hole in the ground and being slapped onto a growing pile. This spatter cone (with Karen for scale; photo taken by Jay Ach) is located on the Big Nasty Trail.

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The main attraction of Lava Beds is the lava tubes that form a wide variety of caves ranging from easy (i.e., one can walk upright) to difficult (i.e., it’s necessary to crawl through some parts). We elected to stick to the easier caves, which still provided lots of interesting features. Good lights are necessary in all caves; for protection, hard hats and warmer clothing are useful in some caves. Below is a photo of Jay and me at the entrance of Valentine Cave, our favorite because of the large variety of lava features, including canals along the tube edges that formed by fast-flowing lava as it moved through. Note the “lava stalactites” that formed on the tube’s roof by the bits of lava that lingered after the flow had continued farther downhill.

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Also visible in Valentine cave is lava “frozen” in place while flowing through the tube. It is easy to imagine the lava when it was actively flowing. The photo was taken by Jay using “light painting” to illuminate the space.

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The bleakness of the landscape was punctuated by the colors of wild flowers in the month of June when we visited the park. We particularly liked the penstemon flower with its brilliant purple-blue color. The photo was taken along the Big Nasty Trail.


Others interesting features of the park are the desert vegetation and the sky. The photo below was taken by Jay in the campground as the sun was setting, using some clever lighting techniques. The trees are junipers.

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The night sky is particularly stunning in this location far from any city. Jay took this photo of the Milky Way in the campground, again using clever lighting techniques to show the trees and the sky in the middle of the night.

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It was close to a new moon during our visit, which helped make stars in the night sky even more clear. Jay took this photo just before sunrise; the planet of Venus is also prominent in the sky. The disk of the moon is only visible because of the long exposure.

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Climbing Mount McLoughlin—one of the lesser known Cascade volcanoes

Mount McLoughlin is located 63 kilometers (38 miles) east of Ashland, Oregon, where I now live. As shown on this map by the U.S. Geological Survey, Mount McLoughlin is located between the volcanoes of Mount Shasta and Crater Lake, which is the remnant of Mount Mazama that exploded to become a caldera 7,700 years ago. All of the Cascade Range volcanoes have been formed as a result of the Juan de Fuca plate (offshore oceanic crust) subducting beneath the North American continental plate.

Mount McLoughlin is a volcano with primarily basaltic andesite lava that has been built within the past 200,000 years or so; the most recent flows occurred within the past 20,000 years. Glacial action during late Pleistocene glaciations (last one 18,000 years ago) left an imprint on the north side of the mountain, which is eroded and very steep.


The mountain is most impressive in the winter when it is capped by snow. Here is a photo from the 2015-16 winter, when Jay and I were cross-country skiing along the Buck Prairie trails that have excellent views of Mount McLoughlin to the east.

IMG_3067.JPGAt any time of year, though, the volcano is a prominent feature on the landscape. This photo is a view to the north from the Indian Memorial Highway. Note the smooth, symmetrical sides of the volcano on the south flank.

P1070924.jpgAnita, a friend who has accompanied me on previous adventures (see January and February 2012 posts of our explorations in Argentina), accompanied me on a climb to the top of Mount McLoughlin on 22 August 2016. At 2894 meters (9495 feet), Mount McLoughlin is one of the lowest Cascade peaks and one of the most accessible, although it’s still a grueling climb, with an elevation gain of nearly 4000 feet (12oo meters) from the parking lot trail head to the peak’s summit. On the photo above, the trail extends up the right (east) side of the cone.

P1070883.jpgThe path is clearly visible through the pine trees and lava boulders up to an elevation of about 2400 meters (8000 feet). At this point, the hiker is above tree line and the summit is visible. This is a good psychological boost, because the trail gets harder to follow and rougher. But the views keep getting better and better…

P1070903.jpgMount Shasta is visible along most of the upper part of the climb. It is at the right side of this photo (looking southwest), although haze obscures the view. Fish Lake, where we camped, is in the foreground; Howard Prairie Lake is a thin sliver in the photo’s center. Pilot Rock is also visible, if you know where to look.

P1070910.jpgOnce at the top, there is a stunning 360-degree view of surrounding mountain ranges. This view, at the summit, is toward the west, with the northern part of the Rogue Valley visible in the upper left part of the photo.

IMG_1553.jpgAnother view from the summit looks eastward, toward Klamath Lake in the distance; the smaller lakes are Lake of the Woods (right side) and Fourmile Lake (left side).

P1070914.jpgHeading east, looking down from the summit, it’s possible to see the contrast between the south side of the volcano, which is less steep and forested, and the north side, which is very steep and eroded from glacial scouring. The upper part of the trail parallels this prominent east–west-trending ridge.

P1070921.jpgAnother view of the steep, eroded north flank gives a sense of how much of the volcano’s mass has been removed by glaciers. Mount McLoughlin is within the Sky Lakes Wilderness Area that includes these ranges north of the peak. With binoculars we could see in the far distance the Two Sisters and Mount Bachelor volcanoes that are located west of Bend.

P1070916.jpgSome hikers speed hike the peak, making it up and down in less than 6 hours. We took our time, pausing to rest and savor the views, taking 9.5 hours in total. It was satisfying to “bag” this peak that is such a distinctive part of the local landscape.