Tag Archives: Lakes

When Rift Lakes Dry Up, Earthquakes and Eruptions Can Follow

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Aerial overview of Nabuyatom Crater, located south of Lake Turkana, Kenya

Martin Harvey/Alamy

The arid conditions of East Africa have led to a decline in the water levels of Kenya’s Lake Turkana for millennia, triggering rising earthquakes and volcanoes beneath its surface. This risk associated with climate change could potentially impact other water bodies globally as precipitation and drought patterns shift.

Lake Turkana is often referred to as the cradle of humanity. Fossils from at least six different human species, dating back 4.2 million years, have been unearthed here, with some believed to have lived alongside each other. As the size of these lakes decreased over thousands of years, our ancestors faced not just a more arid environment but also increased geological activity.

“We believe that during these eras, there would have been a rise in the frequency of earthquakes and volcanic eruptions,” states Christopher Scholz, a researcher at Syracuse University in New York. “The challenging conditions observable today in the region would have been further intensified.”

Situated in the Great Rift Valley between Kenya and Ethiopia, Lake Turkana is the world’s largest desert lake, a greenish body of saline water surrounded by sandy shrublands and breezy outcrops. However, 9,000 years ago, it was considerably larger and enveloped by rich grasslands and forests.

Between 4,000 and 6,000 years ago, the climate shifted towards drier conditions, causing the lake’s level to fall by 100 to 150 meters. Such a drop in water levels lessens the pressure on the lakebed below, potentially influencing seismic behavior. To investigate the impact of this climatic alteration, Scholz and his team pinpointed specific sediment layers that correspond to various historical periods from cores previously extracted from the lakebed.

They conducted sonar scans from a boat over 27 faults on the lake floor to analyze how the sediment layers were displaced vertically on either side of each fault. Their findings suggested that as the climate grows drier, the sides of faults slip past one another at an accelerated average rate of 0.17 millimeters per year.

“The key mechanism here involves tightening and loosening this deformation area, which causes earthquakes,” Scholz explains. “A drier climate coupled with lower lake loads will facilitate a slicker fault line.”

Computer simulations indicate that as water mass diminishes, an increase in magma movement occurs beneath the lake. One of the volcanic islands in Lake Turkana erupted in 1888.

Research previously demonstrated that declining sea levels heighten volcanic activity at ocean ridges. However, this provides the first solid evidence of a similar trend occurring around this lake, according to Ken McDonald from the University of California, Santa Barbara. “It’s akin to loosening the cork on a champagne bottle,” he remarks. “Reducing the pressure increases the likelihood of magma ascending within the Earth’s crust and erupting.”

While climate change is currently leading to higher water levels in Lake Turkana, it may take millennia for seismic and volcanic activities to stabilize significantly.

Nevertheless, the authors of the study advocate that seismic risk assessments should take into account how climate change affects water levels. Moreover, policymakers should factor in seismic vulnerabilities when planning the construction or deconstruction of dams.

“They should install [seismometers] before making any substantial alterations,” McDonald advises.

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Source: www.newscientist.com

Adam Roberts’ New Scientist Book Club Review: Lakes of Darkness – A Mixed Bag

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New Scientist Book Club has just read Adam Roberts’ Lake in the Dark

Laurie photos

Following the journey through Khalian Bradley’s *Time Saving*, the New Scientist Book Club ventured in the opposite direction for our latest read: the far future and some hard science fiction with Adam Roberts’ *Lake of Darkness*. Set in a seemingly utopian society, the narrative revolves around two spacecraft orbiting a black hole, and one captain receiving orders to kill all crew members as commanded by a voice from the depths of that black hole. Not quite utopia, but rather a chilling twist from Roberts’s protagonist, Saccadest in the century, as we delve deeper into this mystical entity.

The reception among our readers is varied; some found it thoroughly enjoyable while others felt its pacing was sluggish. Personally, I resonate with Paul Jonas, a member of the New Scientist Book Club. He shared on Facebook that he was “fascinated by the story” and “appreciated the hard science components relating to space travel, black holes, and utopian societies.” Paul’s insights into the philosophical elements tied to Deleuze’s thinking in this novel truly impress me.

I tend to be quite discerning when it comes to fiction, and rarely find books claiming to be humorous truly engaging (Terry Pratchett being the joyous exception). However, *Lake of Darkness* was different; I found myself intrigued at various moments, particularly appreciating how Roberts’ distant characters grappled with our own history while deciphering what they termed “so-called” *More’s Code*, the ancient system of long and short pulses each symbolizing a single glyph, alluding to the famous Beatles tune, *We All Live in a Yellow Submarine*.

Like Paul, I was captivated by the book’s portrayal of a future utopian society and the dilemmas it presents. During our discussion, Roberts expressed his intention to explore various subgenres of science fiction within his writing. While this perspective on utopia unfolds with its antagonist (spoiler alert – Satan), the idealized vision isn’t as appealing, given that all labor is assigned to “smart machines,” leaving people devoid of functionality. Time becomes filled with hobbies and fandoms, captured in the phrase, “Your people understand the value of everything but the cost. Without a cost, nothing holds worth. The best carries a significant price.” I found it quite delightful to navigate (and read) while contemplating this future society.

Charlotte Sye, another Book Club member, enjoyed listening to the audiobook and shared her enthusiasm: “I love the humor and hard science.” She added, “Life inside a black hole is particularly fascinating, as one character mentions, while there’s tremendous energy, is there really space and time?!”

Barbara Howe, however, had her reservations. She acknowledged the book’s “historical misconceptions” and “utopian critiques,” but felt that the depicted utopia was overly centered on trivial sexual themes, reflecting a male-centric viewpoint, neglecting notions like child-rearing or nurturing that are essential to true progress.

Barbara also pointed out a sentiment echoed by several other readers: she appreciated reading *Lake of Darkness* as an e-book, stating, “I had to look up more words in this single book than in my previous reads.” Alain Pellett echoed this, finding the vocabulary somewhat challenging and “offensive.” Jess Brady shared similar thoughts, enjoying the concept while criticizing the “slow prose.”

While such critiques weren’t particularly noticeable for me—possibly due to my willingness to overlook certain aspects—I did sympathize with Barbara’s assessment regarding the physics: “I tackle explanations of time travel alongside FTL (faster-than-light) travel. I accept these premises; they provide a thin veil of scientific reality over a fantastical plot device.”

Another prevalent criticism among readers was the lack of relatable characters. Alan expressed frustration, noting, “No one seemed sympathetic; their deaths evoked no remorse. They were all insufferable and dim-witted.” Karen Shees concurred, saying, “While the book initially caught my interest, I found the characters so unengaging that I wasn’t invested in their fate.”

I share this sentiment to some extent. Many characters were glaringly absurd, including guunarsonsdottir—distracting. Yet, I believe this serves a purpose, as I relished witnessing the turmoil of these intellectually lazy individuals as they navigated actual threats—through the seemingly redundant formation of another committee discussing their next steps. Moreover, I’m intrigued by the character Bartle Wasp; even the name piques curiosity.

Paul likely feels similarly. “Saccade was a compelling character. Living in a utopia surrounded by AI shapes her perspective. There’s no obligation to fully connect with every character; following their journey can be engaging even if they’re not traditional heroes.”

After finishing *Lake of Darkness*, I found numerous substantial concepts lingering in my thoughts. Did the black hole narrative hold coherence? Was the conclusion truly comprehensible? I’m still pondering—much like Barbara, who concluded that the novel “took unexpected turns and provoked thought.”

“In the latter part, I felt transported back to the 1980s,” she remarked, referencing Douglas Hofstadter’s *Godel, Escher, Bach: Eternal Golden Braid*. “It was a brief throwback, but the ending confuses me. Why did Joins act as she did? Did the entity achieve its desires?”

Paul similarly found the conclusion perplexing. “The ending likely bewildered many due to the complexities of black hole physics,” he noted. “Additionally, the geometric concepts about the inside/outside of infinite structures were truly mind-bending.”

However, let’s shift from the complexities of black holes to the anticipation for our next read. We’ll be diving into Circular Motion by Alex Foster. This captivating debut envisions a gradual acceleration of Earth’s spin, with increasingly disastrous consequences. I’m excited to share it and can’t wait to hear your thoughts! You can preview excerpts here. The narrative examines how this accelerated state might be humanity’s doing. I’ll be discussing the novel with him later this month, so feel free to drop any questions you have in our Facebook group.

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Source: www.newscientist.com

New research suggests large lakes played crucial role in origin of life

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The origin of life on Earth required the supply of phosphorus for the synthesis of universal biomolecules. The closed lake may have accumulated high concentrations of this element on the early Earth. However, it is not clear whether prebiotic sink in such settings was sustainable. New research by scientists from Eth Zurich, Cambridge University and the University of Science and Technology in China shows that high concentrations of phosphorus can be combined in steady states in large closed basin lakes.

Aerial view of Lake Mono. Image credit: Dick Lyon / CC by 4.0.

Phosphorus is an important component of all known forms of biochemistry and plays an important role in such polymers that encode metabolism, cell structure, and information.

However, the environmental conditions that provided sufficient phosphorus available in aqueous solutions to promote the chemical origin of life are uncertain.

“Large soda lakes with no natural runoff can maintain phosphorus concentrations for a long enough long, even if life begins to exist at some point, and could continually consume phosphorus.”

“Such lakes lose water only by evaporation. This means that phosphorus is left in the water, not washed away through rivers or streams.”

“As a result, very high concentrations of phosphorus can accumulate in these soda lakes.”

Not all soda lakes are suitable. Researchers rule out small ones.

“As soon as life develops within them, the supply of phosphorus will deplete faster than it is replenished. This will snag both chemical reactions and developing life,” Dr. Walton said.

“On the other hand, in large soda lakes, phosphorus concentrations are high enough to maintain both basic chemical reactions and life over the long term.”

“These high concentrations are achieved by the large amounts of influential river water, including phosphorus, but the water only leaves the lake by evaporation.”

“Phosphorus doesn’t evaporate easily, so it accumulates in the lake and accumulates.”

In their study, Dr. Walton and colleagues focus on Lake Mono in California, with high phosphorus concentrations at steady state despite extremely high biological productivity.

“This is important because in small lakes, phosphorus is exhausted before new quantities form,” they said.

They consider the large soda lake, which had a constant high phosphorus supply in the early history of the Earth, to be an ideal environment for the origin of life.

They assume that life is more likely to have been born in such a larger body of water than in a small pool, as Charles Darwin suspected.

Therefore, the origin of life may be closely related to the special environment of large soda lakes, which provide ideal conditions for prebiotic chemistry due to the balance of geological environment and phosphorus.

“This new theory will help us solve another part of the puzzle of the origins of life on Earth,” Dr. Walton said.

a paper A description of the findings was published in the journal Advances in science.

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Craig R. Walton et al. 2025. Large, closed basin lakes provided sustained phosphates during the origin of life. Advances in science 11(8); doi:10.1126/sciadv.adq0027

Source: www.sci.news

Study shows wave activity causing erosion along the coastlines of Titan’s largest lakes and oceans

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Titan, Saturn’s largest moon, is the only known planet other than Earth that still retains liquid water. Liquid hydrocarbons fed by rain from Titan’s thick atmosphere form rivers, lakes, and oceans, most of which are found in the polar regions. In a new study, a team of MIT geologists surveyed Titan’s coastline and found that the moon’s large lakes and oceans were likely formed by waves.

Artist’s rendering of the surface of Saturn’s largest moon, Titan. Image by Benjamin de Bivort, debivort.org / CC BY-SA 3.0.

The existence of waves on Titan has been a somewhat controversial topic ever since NASA’s Cassini spacecraft discovered liquid puddles on Titan’s surface.

“Some people who have looked for evidence of waves haven’t seen any waves at all and have said, ‘The ocean is as smooth as a mirror,'” said Dr. Rose Palermo, a geologist with the U.S. Geological Survey. “Others have said they saw some roughness in the water but didn’t know if it was caused by waves.”

“Knowing whether there is wave activity in Titan’s oceans can provide scientists with information about the moon’s climate, including the strength of the winds that generate such waves.”

“Wave information could also help scientists predict how the shape of Titan’s ocean will change over time.”

“Rather than looking for direct signs of wave-like features in Titan images, we wanted to take a different approach and see if just looking at the shape of the coastline could tell us what it is that is eroding the coast.”

Titan’s oceans are thought to have formed when rising waters flooded a landscape crisscrossed by river valleys.

The researchers zeroed in on three scenarios for what happened next: no coastal erosion, wave-driven erosion, and uniform erosion caused by either dissolution, where liquids passively dissolve coastal material, or a mechanism where the coast gradually peels away under its own weight.

They simulated how different coastline shapes would change under each of the three scenarios.

To simulate wave erosion, the researchers took into account a variable called “fetch,” which describes the physical distance from one point on the shoreline to the other side of a lake or ocean.

“Wave erosion depends on the height and angle of the waves,” Dr Palermo said.

“We used the fetch to estimate wave height because the bigger the fetch, the further away the wind will blow and the bigger the waves will be.”

Cassini observed Titan’s surface with microwaves and found several grooves that are deep canyons filled with liquid hydrocarbons, including Vid Fulmina, a branching network of thin lines in the upper left quadrant of the image. Image credit: NASA / JPL-Caltech / ASI.

To test how coastline shape would differ between the three scenarios, the scientists started with a simulated ocean area with a flooded river valley all around it.

For wave erosion, we calculated the fetch distance from every point along the coastline to every other point and converted that distance to wave height.

They then ran simulations to see how waves would erode the original shoreline over time.

They compared this to how the same coastline would change due to erosion caused by uniform erosion.

The authors repeated this comparative modelling for hundreds of different initial shoreline configurations.

They found that the shape of the termini varies greatly depending on the underlying mechanism.

Most notably, uniform erosion produced a bulging shoreline that was evenly distributed all around, even in flooded river valleys, whereas wave erosion smoothed out portions of the shoreline exposed primarily to long downstream distances, leaving the flooded valleys narrow and rough.

“Although the initial coastline was the same, we found that uniform erosion and wave erosion resulted in very different final shapes,” Dr Perron said.

“Although it looks like a flying spaghetti monster because of the flooded river valley, the endpoints created by the two types of erosion are very different.”

This image is a composite of images taken during two flybys of Titan in 2006. A large circular feature near the center of Titan’s disk may be the remnant of a very old impact basin. The mountain range southeast of the circular feature and the long, dark linear feature northwest of the old impact site may be the result of deformation of Titan’s crust caused by energy released when the impact occurred. Image credit: NASA/JPL/University of Arizona.

Dr. Perron and his colleagues verified their results by comparing their simulation results with actual lakes on Earth.

They found the same shape differences between Earth’s lakes known to have been eroded by waves and those affected by homogeneous erosion, such as dissolved limestone.

Their modelling revealed distinct and distinctive shapes depending on the mechanism by which the shoreline evolved.

So they wondered: Where does Titan’s coastline fit into these distinctive shapes?

In particular, they focused on four of Titan’s largest and best-mapped oceans: Kraken Mare, which is comparable in size to the Caspian Sea; Ligeia Mare, which is larger than Lake Superior; Punga Mare, which is longer than Lake Victoria; and Lake Ontario, which is about 20% the size of the land-based lake of the same name.

The researchers used Cassini’s radar images to map the coastlines of each of Titan’s oceans, and then applied their model to the coastlines of each ocean to see which erosion mechanisms best explain their shape.

They found that all four oceans fit closely to the wave-induced erosion model, meaning that waves created the closest coastlines to Titan’s four oceans.

“We found that when the shoreline is eroding, its shape is more consistent with wave-driven erosion than uniform erosion or no erosion,” Dr Perron said.

Scientists are trying to figure out how strong Titan’s winds would need to be to churn up waves strong enough to repeatedly scrape away the shoreline.

They also hope to learn from the shape of Titan’s coastline which direction the winds primarily blow from.

“Titan shows us that this case is completely pristine,” Dr. Palermo said.

“It may help us learn more fundamental things about how coasts erode without human influence, which in turn may help us better manage coastlines around the world in the future.”

of Investigation result Published in today’s journal Scientific advances.

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Rose V. Palermo others2024. Evidence of wave erosion on Titan’s coast. Scientific advances 10(25); Source: 10.1126/sciadv.adn4192

Source: www.sci.news

The wildflowers and lakes of Death Valley showcase a dramatic contrast in climate

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According to climate scientists, the impact of global warming on California’s interior is becoming more evident as desert droughts worsen and rainfall intensifies. Residents of Death Valley are witnessing these changes firsthand. The future of this resilient symbol lies in the ability of the desert’s plants, animals, and local economies to adapt to the evolving conditions in one of the Earth’s harshest environments.

“It’s fascinating to witness these changes up close,” remarked Donnelly. “It’s a clear indication of climate disruption.”

Two Unprecedented Storms

Susan Sorrels, who owns an ecotourism town near Death Valley National Park called Shoshone, described the weather in the area as always erratic. However, recent years have shown a distinct pattern. In early 2022, Death Valley, along with the rest of the American Southwest, experienced a historical drought lasting 22 years, leading to record-low soil moisture levels and the gradual demise of plants such as creosote bushes. The severity of these conditions was a testament to the extreme weather in the region.

“Desert shrubs are incredibly resilient but eventually succumb,” explained Lynn Sweet, a research ecologist at the University of California, Riverside.

In August of the same year, the region was struck by an unprecedented flood, receiving 1.7 inches of rain within a few hours. This storm caused significant damage to park infrastructure and left a lasting impact on the area.

About a year later, the remnants of Hurricane Hillary caused another extraordinary event, dumping 2.2 inches of rain in a day, exceeding the typical annual rainfall. This extreme shift from drought to heavy rainfall exemplifies the unpredictability of the changing climate.

Road workers work along Highway 190, where much of the road was washed away by Tropical Storm Hillary the week before, in Death Valley, Aug. 31, 2023.
Robert Gauthier/Los Angeles Times via Getty Images File

The aftermath of these storms led to challenges for Sorrels and her ecotourism business in Shoshone, with highway closures impacting accessibility during the peak tourist season.

Sorrels mentioned the local struggle to navigate through the economic impact of these weather fluctuations. She highlighted community efforts to expedite road repairs, ultimately reopening the park and highway for visitors.

In a surprising turn of events, Donnelly observed the growth of wildflowers in the region despite adverse conditions. The flowers, thriving in unusual ways, showcased a resilience that defied expectations.

Additionally, the presence of enough water led to the revival of Lake Manly, previously a dry lake bed filled with dust. This resurgence prompted the National Park Service to allow kayaking on the lake, a rare occurrence that highlighted the dramatic changes taking place in the region.

Source: www.nbcnews.com

Winter life around the Great Lakes is changing due to a shortage of ice.

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Some fish species’ reproduction, shoreline erosion, and weather patterns are all at risk due to lower ice levels. This includes changing the amount of lake-effect snow that falls on nearby communities.

Research shows that the maximum annual ice area trended downward at a rate of approximately 5% for each decade from 1973 to 2023. For more information, visit NOAA’s research page.

Due to poor ice conditions, ice fishermen are turning to inland waters as their seasons on Lake Superior are impacted. Joe Friedrichs said, “In the Duluth area, their seasons don’t exist, and that definitely impacts their ability to get on the ice.”

As of Thursday, only 3.4% of the northern Great Lakes region was covered in snow. Visit the National Operational Hydrological Remote Sensing Center for more information.

With the lack of snowfall and above-normal temperatures, businesses that rely on snow activities are taking a hit. John Silliman of Stone Harbor Wilderness Supply said, “People aren’t coming to ski, snowshoe, or snowmobile anymore.”

The region is experiencing the warmest winter on record, and meteorologists predict this trend will continue into spring with higher than normal temperatures. Visit AccuWeather for more details.

The National Climate Prediction Center’s outlook suggests that the Great Lakes region will continue to experience higher than normal temperatures until early spring. This raises concerns about wildfire risk, particularly in parts of Minnesota, Wisconsin, and Michigan. Learn more from the National Interagency Fire Center.

Source: www.nbcnews.com

Storms in California contribute to the creation and maintenance of lakes in Death Valley.

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Following the recent historic heavy rains in California, an unusual event continues to unfold at the lakes of the famous Death Valley.

Officials from the park confirmed that a lake formed in the Badwater Basin in August, typically a salt flat, after heavy rains and flash flooding caused by the remnants of Hurricane Hillary in Death Valley National Park.

Thanks to atmospheric river events over the past two weeks, heavy rain across much of California has caused the lake to last longer than it would have under normal conditions. According to the park’s statement on Thursday, “Most of us thought the lake would be gone by October,” park ranger Abby Wines said in a statement. “We were shocked to see it still here after almost six months. Rain this week will extend the length of time the lake is here. It’s too shallow for kayaking, but It gives us great reflections of the mountains.”

People walk along Lake Manly, a temporary shallow lake in Badwater Basin in Death Valley National Park, California, on December 24.Abbey Wines/NPS Photo

Death Valley typically only receives about 2 inches of precipitation a year, but in the past six months it has seen just under 5 inches of rain, almost entirely due to Hillary and recent atmospheric river events. This was announced on Thursday.

During Hurricane Hillary, about 2.2 inches of rain fell per day, hitting California as a rare tropical storm, resulting in floods that damaged roads and other infrastructure.

The lake, which at one point was 11 miles long, 4 miles wide and 2 feet deep, spilled out following the heavy rainfall, as reported by the National Park Service.

Death Valley received 1.66 inches of rain earlier this week, according to the National Weather Service said earlier Wednesday. With a 72 hour precipitation report.

Park officials say temporary lakes in Badwater Basin are rare. Once an inland lake named Lake Manly, the basin has long since dried up. The park states that it has existed in the geologic past, and the most recent one dried out approximately 10,000 years ago.

Known for having some of the hottest, if not record-setting, scorching summer temperatures ever recorded on Earth, this week’s highs in Death Valley are in the 50s to 60s. The average high temperature in Furnace Creek usually begins to reach 90 degrees in April. According to the park.

The highest temperature ever recorded on Earth was July 10, 1913, at Furnace Creek in Death Valley, reaching 134 degrees, as reported by the World Meteorological Organization.

Source: www.nbcnews.com

Rising Temperatures Lead to Minimal Ice on Great Lakes

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The Great Lakes, known for ice fishing and winter's frozen waves, rang out a nearly bare New Year's bell.

Less than 0.4% of ice covered the Great Lakes on New Year's Day, according to the Great Lakes Environmental Research Institute, which uses satellite data to measure ice concentrations.

“There's basically nothing,” said James Kessler, a physical scientist at the institute, part of the National Oceanic and Atmospheric Administration. “We have about 50 years of data. Today's average for January 1st is about 9%.”

Kessler said that although ice coverage is well below normal, it is not unheard of for ice concentrations to fall below 1% on January 1, still early in the season.

The amount of ice on the Great Lakes (Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario) determines when and how raw materials and cargo are shipped from ports in the Midwest. Fish species such as whitefish are covered in ice to protect their eggs for reproduction. Lower ice levels could increase erosion and contribute to changes in weather patterns in the region.

Kessler said temperatures have been unseasonably high this season, making it difficult for ice to form on the lake's surface. According to his research, the Great Lakes' annual ice area varies greatly from year to year, but tends to decline at a rate of about 5% every decade.

“This is certainly a sign of climate change,” he says.

Ice typically reaches its maximum extent from mid-February to early March. In a typical year, about 40% of the Great Lakes are covered in ice at peak times.

Last year, ice coverage reached about 23% and by mid-February the ice had diminished. just covered 7% of the lake.

In 2023, Earth experienced its hottest year on record, largely due to human-induced climate change. Researchers expect temperatures to rise further this year due to El Niño, a natural climate pattern that releases ocean heat into the atmosphere.El Niño winter Warmer trends across the Great Lakes region.

seasonal outlook Temperatures in the Great Lakes region are expected to be higher than normal this year. below average ice.

Forecasters expect little change this week.

Over the next five days, “temperatures are expected to remain near normal across the Great Lakes region, making the forecast less favorable for ice growth,” one report said. Ice outlook prepared by the National Weather Service in Cleveland.

Source: www.nbcnews.com

The Missoula Glacier Lake’s impact on the dramatic scaly area

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Satellite image of parts of Akaland taken on May 14, 2023 by Landsat 8’s Operational Land Imager.

Ejecta from Missoula Glacier Lake has carved out channeled skeletal lands in Washington state.

Southeastern Washington is home to miles of rolling hills and a neat grid of farmland. Dozens of crops It is grown on precious farmland on the Columbia Plateau. But in some places, undulating streaks of scoured soil interrupt a series of angular plots or center-pivot irrigated fields.

These rocky scars channeled scrubland, and they were formed in a series of dramatic floods 10,000 to 20,000 years ago. Landsat 8’s OLI (Operational Land Imager) captured the image of part of Acarland, about 120 kilometers (75 miles) west of Spokane, on May 14, 2023.

The sources of water that carved these unusual landforms remained a mystery to geologists for decades. Then they came to understand that as the Cordilleran Ice Sheet moved south during the last ice age, it formed dams along the Clark Fork River. Glacial Lake Missoula grew behind this ice dam in what is now western Montana and eventually held as much water as Lake Erie and Lake Ontario combined. Geologists estimate that: a dam was formed and broke dozens of times Over thousands of years, each breach releases up to 600 cubic miles of water across the region.

Detailed view of the image above.

Floodwaters flowed south and southwest, eventually emptying into the Columbia River. In the process, they carved grooves, potholes, and long channels known as “coulees” into the volcanic basalt bedrock. The detailed map (above) shows one of these channels and reveals the striking contrast between flood scoured areas and arable land.

The canyon shown here is small compared to the others. Grand Coulee, the largest of the Channeled Scrublands north of this scene. Completed in 1942, Grand Coulee Dam was the largest concrete structure in the world until it was surpassed by dams in South America. Itaipu Dam 1984 and China three gorges dam Established in 2006.Currently America’s largest hydroelectric facility Provides irrigation water to the Columbia Plateau.

NASA Earth Observatory imagery by Lauren Dauphin using Landsat data from the U.S. Geological Survey.

Source: scitechdaily.com