The Carbon River area is in the northwest corner of Mount Rainier National Park. Like other areas throughout the park, the landscape of the Carbon River area has been shaped by the past forces of volcanic activity as well as by glaciers. The Carbon Glacier, which has the lowest terminus of any glacier in the contiguous United States, continues to play a powerful role in the Carbon River valley. In the videos below, explore the history and geology of the Carbon Glacier, break down the Anatomy of a Flood, and finally look at how the park is trying to mitigate some of the effects of flooding in the Carbon River Project.
[Narrator] Carbon Glacier, a massive river of ice, flows down almost the whole length of Mount Rainier. The Carbon Glacier stretches over 5 miles down to a terminus, or end, elevation of 3,500 feet. This makes it both the longest and lowest terminus glacier in the contiguous United States. It is also the deepest glacier in the country, with ice almost 700 feet thick in places.
[Carolyn Driedger] So as spectacular as it is, Carbon Glacier is just a pocket-sized descendant of the glacier that was here for hundreds of thousands of years on the northwest side of Mount Rainier. In the same space where you're standing and breathing right now, a large glacier existed to a thickness of about 2,500 feet or more. The glacier extended as far down valley as the metal bridge that you crossed on the way here to the ranger station. So compared to those Ice Age glaciers, Carbon Glacier today might seem pretty small, but in fact it's been relatively robust historically and has been one of the healthiest glaciers on Mount Rainier. Carbon Glacier is rather unique, because it is separated into two pieces: its accumulation area exists near the summit and then there is a 4,000 foot cliff called Willis Wall that separates it from the lower part of the glacier which exists in a valley and then the terminus extends down to around 3,500 feet, which is the lowest elevation of any glacier terminus in the contiguous United States. Snow and ice from the accumulation area near the summit of Mount Rainier continues to feed the glacier below via many snow avalanches and ice calving events off the Willis Wall and we also have a lot of rock falling from it as well and that gets incorporated within the snow, the snow metamorphoses to ice, becomes part of the glacier, and the entire mass of snow, ice, and rock moves down valley as the glacier. At low elevations, the ice melts and the rock remains behind and covers the surface of the glacier, with it this covering, which insulates it from solar radiation.
[Narrator] From early visitors to scientists alike, Carbon Glacier has inspired awe. Bailey Willis was the first geologist to explore the area. The cliffs at the head of the Carbon Glacier are still known as Willis Wall. Bailey Willis however did not find the Carbon Glacier very attractive. On his first survey of the glacier in 1881 he notes:
[Bailey Willis] This first sight is a disappointment. The glacier is a very dirty one. The face is about 300 feet long and 30 to 40 feet high. It entirely fills the space between two low cliffs of polished gray rock. Throughout the mass, the snows of successive winters are interstratified with the summer's accumulation of earth and rock. From a dark cavern whose depths have none of the intense blue color so beautiful in crevasses in clear ice, Carbon River pours out, a muddy torrent. The eye willingly passes over this dirty mass to the gleaming northeast spur of the mountain, where the sunlight lingers after the chill night wind has begun to blow from the ice fields. - Bailey Willis, "Explorations on the Northern Slopes, 1881-1883"
[Narrator] The Carbon Glacier's low elevation made it relatively easy to reach for visitors wishing to experience a glacier. The Carbon Glacier has also been a popular route for attempting the summit of Mount Rainier. However, the characteristics that make Carbon Glacier so unique also make it extremely dangerous.
[Stefan Lofgren] The climbing routes that use the Carbon Glacier as part of their access to the route really is limited to one route that people normally do, which is Liberty Ridge. It is one of the 50 Classic Climbs in North America and rightly so. It's one of the more unique routes on Mount Rainier because it exists on a small ridge between the Willis Wall and the Liberty Wall, which are two unique features on Mount Rainier. The route is very, very exposed. It's consistently 45-55, maybe even 60 degrees in some places, so with each step moving forward you're actually moving more up than you are across and after you get up four to five thousand feet you're actually one mile above the terrain below you. So, and even with that sometimes the footing is so tenuous that you're only getting your front two points of your crampons and your two tools of your iceaxe into the snow and ice as you climb so being a mile up, having only a few pieces of steel into the surfaces that you're climbing up can be very exhilarating and that attracts a lot of people and of course that's the downfall of many of the folks because it is such a committing route and people don't like to descend it. People often get stuck on the rock ascending into worsening weather because they don't see descending as an option and that's one of the fatal pitfalls of that route, is people don't allow enough time and that's been the downfall of many people.
[Narrator] Dangerous and intriguing, Carbon Glacier is one of the marvels of Mount Rainier. This massive ice flow molds the landscape even as the mountain shapes the glacier in turn. It is the source of the mighty Carbon River, providing water for many ecosystems. However despite some unique factors such as rock debris insulating the glacier, the Carbon Glacier is not immune to changing climate conditions.
[Paul Kennard] We're in the upper part of the Carbon River valley, which is in the north western part of the park and we're actually in view, I think over my shoulder you can see the lower part of the Carbon Glacier beneath Mount Rainier The Carbon Glacier is actually one of the thickest- is the thickest glacier on Mount Rainier that has about 25 glaciers and it has- there's more glacier ice on Mount Rainier than on all the other Cascade volcanoes combined. and the Carbon Glacier starts near the summit so even under the most dire climate scenarios it's not expected to disappear but it's definitely being affected by the climate and what's been happening recently though, what's actually been happening for quite a while, but it's been accelerated recently is the glaciers are melting quite, quite quickly. Sort of on average in the 20th century, the glaciers lost maybe 25% of their volume but the park has been measuring the glaciers, they call it a mass balance study, measuring the health of the glaciers, are they getting bigger or smaller, but unlike the glaciers on the other side of the park instead of getting shorter this glacier is more or less deflating. So it's not responding as dramatically as the glaciers on the south side of the park and that's cause they get a lot of sun so they're just much more attuned to the climate, they're much more sensitive. But essentially all the glaciers are melting on Mount Rainier and as they do so they're putting a prodigious amount of sediment into the rivers. Glaciers have big piles of rubble on the side, it's called a lateral moraine, and what has happened is this one has shrunk back from that and it's the only glacier in the park where it's having massive landslides that are coming down between the glacier and this moraine and these landslides are depositing in this whole area where we are and it's hard to envision just from these pictures, but this was a forest where we're standing, was an old growth forest, centuries old, in 2009. Since then the river has completely shifted through here and we're getting wholesale changes of the Carbon River where the main channel is shifting and killing forests that have been around for centuries. This signals a very big change for the river. Yeah, I sort of joke to the park that nature bat's last but that doesn't mean that we're hopeless and just say things are chaotic and we can't predict anything. We are working very hard this summer and we have some very bright Masters students working on it where we're looking where these sediment accumulations are and since they are dynamic and moving we're trying to help guide how much money they put into repairing the trail. So if you see one of these sediment accumulations that's forcing the water to the valley's sides where it's hitting the road or the trail, if it's right there now, it's sort of foolish to spend to your money on it now but if you can actually predict using some data that that bulge will move in the future you would have a much higher chance of success and since budgets are always a little bit limited, we feel if we can use science to help guide the timing and nature of their repairs we can just spend the money in the most wise sense and provide the most access to the public.
[Narrator] Like all glaciers in Mount Rainier National Park, the Carbon Glacier is a dynamic force shaping the landscape of the mountain. It is a source of life giving water but also holds the potential for terrible devastation. It has been a draw for explorers and visitors for over a century. Mount Rainier National Park continually works to understand the Carbon Glacier so that it will be there to challenge and amaze us into the next century.
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The Carbon Glacier has shaped both the landscape of Mount Rainier as well as the history of Mount Rainier National Park. This impressive glacier also plays a powerful role in shaping the future of both the mountain and its national park.
What is a flood? A flood is just too much water in the wrong place. The bigger question is why? Why does too much water end up in the wrong place? The factors that determine whether or not a place will flood are the same no matter where you are. Knowing the components of a flood can also help predict how often and how big or damaging those floods will be when they do occur.
The Carbon River area in the northwest corner of Mount Rainier National Park is notoriously prone to flooding. A flood occurs when there is too much water flowing in a particular place. So what is it about the Carbon River that causes it to flood so frequently? Different places can handle different amounts of water and the Carbon River area deals with a lot. On average, the area gets over 80 inches of precipitation a year. When moisture-laden air from the Pacific ocean collides with the massive slopes of Mount Rainier the result is lots of rain, or at higher elevations, snow.
As a result of the frequent rain, the Carbon River area is home to a dense temperate rain forest. Old growth trees, mosses, ferns, and numerous other plants thrive on the high amounts of rainfall. Some of the moisture falls as snow and becomes trapped as part of the Carbon Glacier. Excess water collects in numerous creeks and streams in the area all eventually flowing into the powerful Carbon River. Even under normal conditions, the Carbon River can handle a lot of water. However, even places with a large capacity for water like the Carbon River area have a limit. During the November 2006 flood, the largest flood in the park's recorded history, it rained 18 inches in three days. The Carbon River area normally handles only 17 inches of rain in the entire month of November.
Many factors affect whether or not a place like Carbon River can adapt to extreme amounts of rainfall like what fell during November of 2006. The Carbon River is a large river capable of transporting a lot of water. Lush forests divert some rainfall, while glaciers store even more water as ice. However frequent rain can also saturate soils and water log even the densest forest. Changing climate is affecting weather patterns, creating larger storms with more intense rainfall than in the past.
A process called aggradation is also restricting the ability of the Carbon River to carry water. Aggradation is the opposite of erosion. Mount Rainier's glaciers create so much rocky material and sediment as they grind down the mountain that the rivers can't move it all. Plus, as climate change melts glaciers faster than ever, even more rocky material enters the river. When the river channels fill up, the river is forced in new directions creating braiding of the river channels. Even under normal circumstances aggradation can cause rivers to dramatically alter course. During flood events, the process of aggradation is accelerated, amplifying the effects of too much water in the system.
Often rivers end up flowing through surrounding forests as well as any human construction in the way. Floods are a natural and often necessary part of a healthy environment. Sediments deposited by flood waters provide much needed nutrients for new vegetation. The powerful force of the water scours river beds of debris and creates new habitat for fish and aquatic insects. Floods are also very damaging, particularly to human roads and structures. Unfortunately the Carbon River Road was built along the edge of the Carbon River. When aggradation fills up the river channels the easiest path for the water is often the road itself. This conflict with human use has played out repeatedly throughout the roads history.
As long as the conditions that cause flooding persist, then floods will continue to happen in the Carbon River area. Glaciers are shrinking due to climate change, releasing more water and rocky material into the river system. The process of aggradation is accelerating. Rain will continue to fall. Human use however is within our control. By better understanding the anatomy of floods, Mount Rainier National Park plans for the future so that a balance can be struck that allows for the natural processes of the river as well as for human use.
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What is a flood? Why do floods occur at Mount Rainier National Park, and how are floods changing the landscape? The video "Anatomy of a Flood" breaks down the answers to these questions using the Carbon River as a prime example.
The following film includes interviews with Eric Walkinshaw, Project Manager and Civil Engineer for Mount Rainier National Park, and Kirt Hanson, Project Engineer and Geologist with Cardno Entrix, discussing the work that has been going on in the Carbon area to protect the road and facilities from future damage through the installation of flood protection structures such as engineered log jams.
The historic Carbon River Road was heavily damaged during a November 2006 storm event that resulted in heavy flooding and closed the road to vehicle use since then. Due to aggradation, rocks and gravel have raised the bed of the Carbon River up as much as 31 feet since the Carbon River Road was constructed next to the river in the 1920s. Several sections of the historic road are now lower than the adjacent river and increasingly vulnerable to flood damage.
Carbon River Project TRANSCRIPT Interview with Eric Walkinshaw, Project Manager & Civil Engineer, Mount Rainier National Park; and Kirt Hanson, Project Engineer & Geologist, Cardno Entrix
Walkinshaw: My name is Eric Walkinshaw. I’m the Project Manager Civil Engineer here at Mount Rainier National Park and we’re at the Carbon River Entrance Area; and we’re involved in a project of installing about five log-constructed flood protection structures. So it protects the entrance station to the park and some other facilities here in the park. We hired the consultant to come in and they did the design work for us for these structures last October of 2010 and now we actually have a contractor on board: Mike McClung & Co., Construction Company (Mike McClung Construction, Inc., Buckley, WA), and they’re constructing these structures for us; and Kirt’s here to kind of oversee that part of the project to make some adjustments if they’re needed on the structures.
Hanson: Yeah, I’m Kirt Hanson, Engineer and Geologist with Cardno Entrix. I’m excited to be part of what I think is a historic project. Engineered log jams have been around in ecologic and bank protection, flood protection systems for going on probably close to twenty years- more likely fifteen- and this is the first project where an engineered log jam has been installed inside of a National Park.
Walkinshaw: We, like I said, we’re constructing a total of about five of these structures, one of which is called an engineered log jam, which is a more beefier structure, and that’s on the leading edge just up upstream, about a hundred yards from us. It’s basically to calm the water, to have some habitat, but also in calming the water it drops out material that the river is carrying, mostly rock and silt. So by doing that it kind of builds up that area so when the river floods again it forces it over more to the center of the channel and away from our banks. So that’s the intent of that, but we had the advantage in this area of having a natural log jam, which is kind of what you see back behind us; there is another one further down where the contractor is currently working. So Entrix designed these linear structures as kind of fences on either side of those to kind of contain that. What they didn’t want to have happen- what we don’t want to have happen, is for those natural log jams to raise up and float and leave. Cause they’re in a good location that’s protecting our facilities but they needed the added help of putting in these structures to kind of encapsulate it so it doesn’t float away-
Hanson: -to reinforce the existing log jams.
Hanson: The first thing the contractor is taking care of is ground water, and McClung has done an absolute fantastic job of maintaining their de-watering systems. That involves an initial excavation to a depth below the bottom of the structure, typically these initial excavations extend 17-18 feet below the ground surface to create a sump. From that point, the ground water is pumped into a sedimentation system where fine sediments are dropped out before being returned to the river. The general, on this particular project, the general depth to the bottom of our excavation is about fifteen feet. That’s where these vertical piles that you can see right behind me, that’s the elevation that those are installed to: fifteen feet below the ground’s surface. This pile, here, is actually, it’s probably about five and a half feet tall from where I’m standing- this is actually over a twenty-five foot pile. So there’s about twenty feet of log buried beneath my feet right here. So following the installation of the vertical piles, there’s an angled log that extends- that log is about thirty-five feet long, extending back into the earth, also excavated to a depth of about fifteen feet below existing pre-construction ground surface. Following the installation of those, other horizontal members are added, racking material out front to help control scour, and also create fish habitat, is installed, and final site grading completed. This is an innovative design, designed to catch additional wooden debris coming down the channel, creating additional habitat, and providing additional stability to the existing park structure and park entrance.
Walkinshaw: Basically all of our rivers are a lot like this. We’re having problems in other areas as far as getting a lot of deposition, getting the river bed higher than our facilities, dealing with levees, dealing with- we’re going to be installing, especially on- hopefully on the the success of these, which I’m really confident that these are going- I mean they are pretty beefy structures, I think they’re going to do the trick- and so we’re going to use them a lot. This is just really the first, as Kirt mentioned, this is really the first location that we’ve done it in earnest, these many structures. So we’re really going to be watching this and seeing how it performs and I’m sure we’re going to use it in a lot of other locations.
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Discover what it takes to install flood protection structures such as engineered log jams. In the future, these structures will help protect park facilities and roads from damage from flooding. RT: 05:33
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Last updated: February 21, 2020