Author’s Note: This is the last of a weekly series on geology for a class I am taking this semester at BYU-Idaho. This week’s prompt required students to show the effects of climate change in our local area. Other posts from this assignment can be found under the “Geology 111” category.
If I had to pick one geographic location to use as the symbol of Washington State, it wouldn’t be the Space Needle, the thick evergreen forests west of the Cascades, or the Columbia River. No, my pick would be Mount Rainier. Located between Tacoma and Yakima, Mount Rainier dominates the horizon in the Puget Sound Region and can be seen throughout much of the state and parts of northern Oregon.
Rainier is the most heavily glaciated peak in the contiguous United States, with the only American mountains beating it out being located in Alaska. Unlike last week’s post, which talked about the lowest point in the lower 48, Rainier is the second highest. Rainier is on the Decade Volcano list. This list, which is maintained by the International Association of Volcanology and Chemistry of the Earth’s Interior, encourages further study of what is considered some of the most dangerous volcanoes in the world to better prepare for future eruptions.
One of the major reasons why Rainier is considered so dangerous is the amount of glacial ice located on its slopes. When large eruptions occur, the extremely hot material ejected by the volcano triggers massive mudflows that cascade downstream to destroy homes, businesses, and important infrastructure like highways.
Okay, that’s great and all, but that’s not what the assignment is about. The links that I’m supposed to apply to this post are as follows:
Satellite measurements have demonstrated a loss of approximately 900 million cubic yards of ice on the mountain since 1970. If you were to distribute that value evenly across the entire mountain, that would amount to the ice losing 25 feet of thickness. Of course, this being nature, the losses haven’t been distributed evenly. The surface of some glaciers has dropped by upwards of 140 feet.
Measurements started well before satellites began being used in 1970. The National Park Service reports (archive) that in 1896, explorers mapped about 50 square miles of glacial ice. By 2015 that value had dropped to near 30 square miles.
Photographs provide ample evidence of ice loss on the mountain, with some photographs being taken as early as the late-1800s. During the Great Depression, the Forest Service commissioned photographers to take panoramic photos from fire lookouts to aid in determining locations when monitoring wildfire activity.
More than 80 years later a Wenatchee-based photographer redid the project, taking photos from the exact same locations as had been done in the 30s. His 1,200 photos showed changes in forest thickness as well as changes in the extent of glacial ice. Just take a look at the difference in the Cowlitz Glacier between 1934 and 2017:
What was once an ice-filled valley is now a bare scar where the glacier once flowed. Changes like this are happening all over the western United States and around the world. According to a book I’m currently reading, Fire Mountains of the West, all but two Cascade volcanoes have experienced shrinking glaciers in the last century. The two lucky ones? California’s Mount Shasta and Washington’s Mount St. Helens.
Mount Shasta’s growing glaciers can be attributed to changes in precipitation values as the global climate changes. The story at St. Helens is even more unique. When it erupted in 1980, lahars filled with melted glacial ice filled surrounding rivers, eventually ending up in the Columbia. Glaciers have since been regrowing on its slopes and in its crater. Once this regrowth ends, I’m sure these glaciers will begin to retreat at the same rate as others have around the world.
Glaciers in Washington, Oregon, Idaho, Montana, Wyoming, and British Columbia are extremely important to the arid regions east of the Cascades. Much of the eastern half of Washington and Oregon get well under ten inches of rain a year, along with summer temperatures commonly exceeding 100 degrees.
Conditions like these make it hard to grow any sort of plant life, hence why outside of farms and developed areas the dominant flora is restricted to sagebrush and grasses. Trees and more lush plantlife can only be found near streams and rivers. Despite this, we are able to grow an abundance of crops in the region because of the many large rivers we have access to.
Rivers such as the Columbia and Snake depend on glaciers and winter snow to flow with the quantity of water that they have. Without irrigation from these rivers, eastern Washington would probably be as desolate as northern Nevada with only isolated areas of farming. If the glaciers continue to melt and snowfall lessens, we will be faced with more water shortages and restrictions which could have a negative impact on the economy of the Inland Northwest.
2 Comments
Great article Mark. I have always been fascinated by this mountain and this subject. I would prefer that the glaciers were advancing rather than retreating. From what I have been able to read online, and the articles are somewhat dated, is that Mt Shasta, much to the south of Mt Rainier but also a dormant volcano of just about the same elevation, and also glaciated, though not as much as Rainier. As of a few years ago, I have read that the glaciers had been growing on Mt Shasta. Do you know if they still are? I have read unconfirmed reports that the past few years they are retreating again, though in the 2016-2017 winter record amounts of snow fell that must have caused a gain. I also have read that some of the icefields up in Alaska, such as the Juneau and Bering had been growing in spots. If you can point me to some articles on these subjects or post your own opinions/facts on these issues, I would greatly appreciate it. Thanks! Kevin
Everything I’ve seen about Mount Shasta indicates that it currently has a general trend of increasing glacier size because of increased precipitation values. I don’t have any links off hand that I can provide, but I have recently been reading a book named ‘Fire Mountains of the West’ that might be of interest to you.