The curving, parallel mountain ridges of the Sierra Madre Oriental are an eye-catching feature of northeastern Mexico’s landscape. The spot where these folds nestle up against Mexico’s second-largest metropolitan area captured the attention of an astronaut aboard the International Space Station, who took this photo on August 26, 2026.

Monterrey, the capital of the state of Nuevo León, is an industrial hub supporting heavy industries such as ironworks and steelworks, as well as manufacturing facilities for goods ranging from textiles to processed foods to glass and plastics. The metropolitan area is home to 5.3 million people, according to the 2020 census. And while the city has seen overall population growth since 1990, the number of people living within 5 kilometers (3 miles) of the city center has declined, researchers have found—a trajectory shared with many of Mexico’s metropolitan areas.

In Monterrey’s case, urban expansion runs up against some unforgiving terrain. Along the city’s southern edge, layers of limestone, deposited in the late Mesozoic era and then folded between about 80 and 50 million years ago, form the Sierra Madre Oriental. Over millions of years, weaker rock layers have eroded away, leaving behind the distinct ridgelines that bound Monterrey today.

The Río Santa Catarina carves through the mountains and onto the semiarid floodplain where the city lies. Because of the dry environment, the river carries little to no water for much of the time. But its channel is crucial for collecting runoff from summer rains and serves as an important natural area for plant and animal life within the city.

The river runs through Monterrey’s urban core and between several island-like protrusions of folded rock. One of these is the Sierra Las Mitras, a state nature reserve established in 2000. The mountain ridge rises approximately 1,500 meters (4,900 feet) over the city and provides a haven for wildlife. As conditions become cooler and wetter with higher elevations, vegetation turns from cacti and thorny shrubs on lower rocky slopes to oak and pine forests higher on the ridge. Cerro de la Silla (Mount Silla or Saddle Hill) is another prominent feature of the landscape, contrasting with the built environment.

Near the city’s border with the Sierra Madre Oriental sits Universidad de Monterrey, a host venue for the NASA Space Apps Challenge. This annual hackathon will take place in November 2026 in person and virtually at sites around the world. Participating teams use NASA and partner agency data to tackle challenges in fields such as software development, astrophysics, space exploration, and agriculture.

Astronaut photograph ISS075-E-70481 was acquired on August 26, 2026, with a Nikon Z9 digital camera using a focal length of 400 millimeters. It is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit at NASA Johnson Space Center. The image was taken by a member of the Expedition 75 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Story by Lindsey Doermann.

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August 26, 2026

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References & Resources

• International Parks, Sierra de las Mitras. Accessed September 10, 2026.
• NASA Earth Observatory (2020, November 27) A Sliver of Mexico’s “Mother Mountain Range.” Accessed September 10, 2026.
• NASA Earth Observatory (2017, May 10) Mount Silla and Monterrey. Accessed September 10, 2026.
• NASA Space Apps Challenge (2026) Monterrey. Accessed September 10, 2026.
• Universidad Autónoma de Nuevo León, La importancia ambiental del Río Santa Catarina. Accessed September 10, 2026.

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The post Monterrey Amid Mountains appeared first on NASA Science.

Seattle, Washington—sometimes known as the “Emerald City”—was glimmering in the morning sunlight when an astronaut aboard the International Space Station took this photo on June 16, 2026. The city’s parks and tree-filled neighborhoods lend a lush, green look to the metropolis, while tall buildings downtown cast long shadows and ships navigate surrounding waterways.

The broad contours of the city’s landscape and the water around it owe their shape to the advance and retreat of glaciers during the last ice age. Between roughly 18,000 and 16,000 years ago, the Puget lobe of the Cordilleran ice sheet covered the area in a mass of ice up to 3,300 feet (1,000 meters) thick. The glacier scoured the basins now occupied by Puget Sound and the region’s lakes. 

The glacier left its mark above water, too. Several of Seattle’s notorious hills (of which there are seven or more, depending on who’s counting) are drumlins. These elongated mounds of glacial debris run north-south, parallel to the direction of the ice’s movement. East-west travelers in the city, facing challenging ups and downs, may attest to this topographic trend.

The ice also transported large boulders called glacial erratics from more northerly locations and deposited them around the region. A particularly large erratic, the Wedgwood Rock, stands about 20 feet (6 meters) tall and draws its name from the North Seattle neighborhood in which it rests.

In more recent times, humans have undertaken projects to rework the topography. Notable alterations include leveling Denny Hill north of downtown and filling in tideflats at the mouth of the Duwamish River south of downtown, which created around 1,300 acres of new land. Seattle’s professional sports stadiums sit atop this fill.

This photo was acquired after several development projects to update waterfront infrastructure downtown, initiated in 2010, were completed. These include a new ferry dock and terminal, a rebuilt seawall, and a tunnel to replace an above-ground highway and create more inviting public access to the waterfront.

Some replumbing of the region’s waterways is apparent from the astronaut’s perspective, as well. In the 1910s, the Army Corps of Engineers built canals on either side of Lake Union to connect Puget Sound (an inlet of the Pacific Ocean) with Lake Washington. Starting in 1916, the Montlake Cut connected Lake Washington to Lake Union, and the Ballard Locks, northwest of Lake Union, began raising and lowering watercraft between the freshwater lakes and tidal Puget Sound. As a result of this project, Lake Washington’s water level dropped about 9 feet (3 meters) and ceased draining from its natural outlet at its southern end.

Today, the waters in and around Seattle support many uses: container ships, cruise ships, car and passenger ferries, floatplanes, and recreational craft ply the sound and lakes. And as for Seattle’s emerald nickname, pockets of old-growth forest still exist within city limits, containing centuries-old trees such as Douglas fir, Western red cedar, and Western hemlock. Seattleites often spot wildlife such as bald eagles, coyotes, and sea lions in the city’s various habitats.

Astronaut photograph ISS074-E-723719 was acquired on June 16, 2026, with a Nikon Z9 digital camera using a focal length of 560 millimeters. It is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit at NASA Johnson Space Center. The image was taken by a member of the Expedition 74 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Story by Lindsey Doermann.

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June 16, 2026: Wide view

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June 16, 2026: Detailed view

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References & Resources

• Booth, D.B., et al. (2003) The cordilleran ice sheet. Development in Quaternary Science, 1, 17-43.
• Cascade PBS (2025, January 9) The Giant Ice Sheet That Shaped Seattle. Accessed July 17, 2026.
• City of Seattle (2026) Waterfront Seattle Program. Accessed July 17, 2026.
• HistoryLink.org (2017, February 5) Lake Washington Ship Canal (Seattle). Accessed July 17, 2026.
• HistoryLink.org (2016, December 30) Cedar-Sammamish Watershed. Accessed July 17, 2026.
• Williams, D.B. (2017) Too High and Too Steep. University of Washington Press.

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In preparing to visit the Moon’s surface, soon-to-be lunar explorers in NASA’s Apollo program first ventured into a variety of unfamiliar landscapes on Earth. A couple of these trips, in the summers of 1965 and 1966, took astronauts to Alaska’s remote Katmai National Park for simulations of field geology in Moon-like environments.

In one exercise, which they called “playing the Moon game,” pairs of astronauts were placed at unfamiliar field sites and asked to pretend as if they were on the Moon. By the account of William Phinney, Apollo’s science training coordinator, they were tasked with collecting representative geologic samples and practicing how to communicate their observations to scientists.

The Alaskan setting for the Moon game was an unusual volcanic landscape called the Valley of Ten Thousand Smokes. The valley is full of debris deposited by the 1912 eruption of Novarupta—the largest volcanic event on Earth in the 20th century.

The images above, acquired on September 29, 2025, with the OLI (Operational Land Imager) on Landsat 9, show the massive ash flow deposited by Novarupta. The layer measures up to 660 feet (200 meters) thick and was emplaced at a searing 1,380 degrees Fahrenheit (750 degrees Celsius). 

The Valley of Ten Thousand Smokes, shown in the 1917 photo below, is so named because of the abundance of fumaroles—gas and steam-emitting vents—that filled the valley for a decade after the eruption. A few hundred persisted more than 10 years, with some lasting until the 1990s.

Scientists initially suspected that the monster eruption occurred at Mount Katmai, a neighboring volcano with a large caldera located 6 miles (10 kilometers) east of Novarupta’s dome. However, they later determined that the eruption actually occurred at Novarupta—whose name means “new eruption”—after stealing magma from beneath Katmai. As the magma chamber emptied, Katmai collapsed, forming the 2.5-mile-wide (4-kilometer-wide) caldera present today.

The volcanic landscape in the Valley of Ten Thousand Smokes is far fresher than the ancient lava flows that formed the Moon’s volcanic features. But for the Apollo astronauts, it offered an “excellent opportunity to view volcanic materials and landforms in nearly pristine condition,” Phinney wrote. They studied evidence of fumaroles and examined vertical sections of the deposits where streams had eroded deep gorges.

Researchers continue to visit this Alaskan wilderness in search of clues that could help decipher the geology of the Moon and Mars. In 2024, the Goddard Instrument Field Team (GIFT) trekked to the Valley of Ten Thousand Smokes to study its icy volcanic landscape. Like the valley, Mars contains glaciers and ice sheets layered with dust and ash, a dynamic and difficult-to-interpret environment.

Advancing lunar science, the GIFT team also collected samples from rock formations comparable to the Moon’s Gruithuisen Domes. These mysterious features are made of hardened lava with a different composition than the surrounding rock. With more to learn about our nearest celestial neighbor, the spirit of the Moon game lives on in the 21st century.

NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Photos from National Geographic Society Katmai expeditions photographs, Archives and Special Collections, Consortium Library, University of Alaska Anchorage, and from the U.S. Geological Survey Volcano Hazards Program. Story by Lindsey Doermann. 

Downloads

September 29, 2025

JPEG (2.64 MB)

References & Resources

• NASA Lunar Volcanism. Accessed June 23, 2026. 
• NASA (2024, August 24) Into The Field With NASA: Valley Of Ten Thousand Smokes. Accessed June 23, 2026. 
• NASA (2015, November) Science Training History of the Apollo Astronauts. Accessed June 23, 2026. 
• NASA Earth Observatory (2024, August 22) Under the Ash: Glacier Science at a Volcano. Accessed June 23, 2026. 
• NASA Earth Observatory (2016, May 14) Katmai National Park, Alaska. Accessed June 23, 2026. 
• NASA Earth Observatory (2012, June 9) Remembering a Monster Eruption. June 23, 2026.
• National Park Service (2023, April 18) Fumaroles. Accessed June 23, 2026. 
• National Park Service (2021, August 24) Following in the Footsteps of Astronauts. Accessed June 23, 2026.

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In preparing to visit the Moon’s surface, soon-to-be lunar explorers in NASA’s Apollo program first ventured into a variety of unfamiliar landscapes on Earth. A couple of these trips, in the summers of 1965 and 1966, took astronauts to Alaska’s remote Katmai National Park for simulations of field geology in Moon-like environments.

In one exercise, which they called “playing the Moon game,” pairs of astronauts were placed at unfamiliar field sites and asked to pretend as if they were on the Moon. By the account of William Phinney, Apollo’s science training coordinator, they were tasked with collecting representative geologic samples and practicing how to communicate their observations to scientists.

The Alaskan setting for the Moon game was an unusual volcanic landscape called the Valley of Ten Thousand Smokes. The valley is full of debris deposited by the 1912 eruption of Novarupta—the largest volcanic event on Earth in the 20th century.

The images above, acquired on September 29, 2025, with the OLI (Operational Land Imager) on Landsat 9, show the massive ash flow deposited by Novarupta. The layer measures up to 660 feet (200 meters) thick and was emplaced at a searing 1,380 degrees Fahrenheit (750 degrees Celsius). 

The Valley of Ten Thousand Smokes, shown in the 1917 photo below, is so named because of the abundance of fumaroles—gas and steam-emitting vents—that filled the valley for a decade after the eruption. A few hundred persisted more than 10 years, with some lasting until the 1990s.

Scientists initially suspected that the monster eruption occurred at Mount Katmai, a neighboring volcano with a large caldera located 6 miles (10 kilometers) east of Novarupta’s dome. However, they later determined that the eruption actually occurred at Novarupta—whose name means “new eruption”—after stealing magma from beneath Katmai. As the magma chamber emptied, Katmai collapsed, forming the 2.5-mile-wide (4-kilometer-wide) caldera present today.

The volcanic landscape in the Valley of Ten Thousand Smokes is far fresher than the ancient lava flows that formed the Moon’s volcanic features. But for the Apollo astronauts, it offered an “excellent opportunity to view volcanic materials and landforms in nearly pristine condition,” Phinney wrote. They studied evidence of fumaroles and examined vertical sections of the deposits where streams had eroded deep gorges.

Researchers continue to visit this Alaskan wilderness in search of clues that could help decipher the geology of the Moon and Mars. In 2024, the Goddard Instrument Field Team (GIFT) trekked to the Valley of Ten Thousand Smokes to study its icy volcanic landscape. Like the valley, Mars contains glaciers and ice sheets layered with dust and ash, a dynamic and difficult-to-interpret environment.

Advancing lunar science, the GIFT team also collected samples from rock formations comparable to the Moon’s Gruithuisen Domes. These mysterious features are made of hardened lava with a different composition than the surrounding rock. With more to learn about our nearest celestial neighbor, the spirit of the Moon game lives on in the 21st century.

NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Photos from National Geographic Society Katmai expeditions photographs, Archives and Special Collections, Consortium Library, University of Alaska Anchorage, and from the U.S. Geological Survey Volcano Hazards Program. Story by Lindsey Doermann. 

Downloads

September 29, 2025

JPEG (2.64 MB)

References & Resources

• NASA Lunar Volcanism. Accessed June 23, 2026. 
• NASA (2024, August 24) Into The Field With NASA: Valley Of Ten Thousand Smokes. Accessed June 23, 2026. 
• NASA (2015, November) Science Training History of the Apollo Astronauts. Accessed June 23, 2026. 
• NASA Earth Observatory (2024, August 22) Under the Ash: Glacier Science at a Volcano. Accessed June 23, 2026. 
• NASA Earth Observatory (2016, May 14) Katmai National Park, Alaska. Accessed June 23, 2026. 
• NASA Earth Observatory (2012, June 9) Remembering a Monster Eruption. June 23, 2026.
• National Park Service (2023, April 18) Fumaroles. Accessed June 23, 2026. 
• National Park Service (2021, August 24) Following in the Footsteps of Astronauts. Accessed June 23, 2026.

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The post Playing the Moon Game  appeared first on NASA Science.

El Niño, characterized by warmer-than-normal water temperatures in parts of the equatorial Pacific, made its return in June 2026. Observations of sea surface height from the Sentinel-6 Michael Freilich satellite that month indicated that the 2026 event was continuing to strengthen.  

The natural, recurring phenomenon can have widespread effects, typically bringing wetter conditions to the U.S. Southwest and drought to countries in the western Pacific, such as Indonesia and Australia. NOAA declared an El Niño on June 11, after sea surface temperatures in the central and eastern equatorial Pacific measured at least 0.5 degrees Celsius above average for several consecutive months.

Meanwhile, NASA scientists have been observing a complementary sign of El Niño: areas of elevated sea surface height. When ocean water warms, it expands in volume and causes the sea surface to rise—making the water’s height a reliable indicator of ocean temperatures. Warmer-than-normal temperatures, hence higher sea surface heights, in parts of the equatorial Pacific Ocean are associated with El Niño.

The map above depicts sea surface height anomalies across the central and eastern Pacific Ocean as observed on June 8, 2026. Shades of red indicate sea levels that were higher than average. Normal sea level conditions appear white, and lower areas are blue.  

Data for the map were acquired by the Sentinel-6 Michael Freilich satellite—launched in 2020 by NASA and led by ESA (European Space Agency)—and processed by scientists at NASA’s Jet Propulsion Laboratory (JPL). Note that signals related to seasonal cycles and long-term trends have been removed to highlight sea level anomalies associated with El Niño and other short-term natural phenomena.

Earlier in spring 2026, the satellite started to detect precursor signs of El Niño as swells of warm water hundreds of miles wide, known as Kelvin waves, moved from the western Pacific to the eastern Pacific. That happens when trade winds in the western equatorial Pacific weaken and then temporarily reverse to blow from the west. Warm water piles up in the east, deepening the warm surface layer, lowering the thermocline, and suppressing the upwelling that usually keeps waters along the Pacific coasts of the Americas cooler.

This buildup of heat beneath the water’s surface is what sea surface height observations capture. It goes beyond surface temperature measurements to indicate how much heat is stored in the subsurface. That’s important because a shallow warm layer might not have much impact on climate and weather, while a large reservoir of heat below the surface can matter more.

According to JPL sea level researcher Severine Fournier, deputy project scientist for Sentinel-6 Michael Freilich, conditions in the western Pacific on June 8 looked similar to those from the same time in 1997, a year when an exceptionally strong El Niño emerged. Warm conditions in the eastern Pacific in 2026 have lagged behind, however, with fewer Kelvin waves built up by the same date.

Still, more warm Kelvin waves appeared to be approaching the eastern Pacific, meaning El Niño was still strengthening. Whether it catches up to 1997 depends on ocean activity in the coming weeks. “For now, it looks like it’s going to be a big one—more so than I would have said last week—but we still need more observations to know what’s going to happen.”

NASA Earth Observatory image by Lauren Dauphin, using modified Copernicus Sentinel data (2023) processed by the European Space Agency and further processed by Josh Willis, Severin Fournier, and Kevin Marlis/NASA/JPL-Caltech. Story by Kathryn Hansen.

Downloads

June 8, 2026

JPEG (1.19 MB)

References & Resources

• Climate Prediction Center/NCEP/NWS (2026, June 11) El Niño/Southern Oscillation (ENSO) Diagnostic Discussion. Accessed June 17, 2026.
• NASA Earth Observatory (2025, September 25) El Niño. Accessed June 17, 2026.
• NASA Earth Observatory (2023, June 21) El Niño Returns. Accessed June 17, 2026.
• NASA’s Jet Propulsion Laboratory (2026, May 27) NASA-European Sea Level Mission Homes in on El Niño. Accessed June 17, 2026.
• NOAA (2026, June 11) El Nino forms, expected to strengthen, say NOAA forecasters. Accessed June 17, 2026.

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The post El Niño Is Underway appeared first on NASA Science.

El Niño, characterized by warmer-than-normal water temperatures in parts of the equatorial Pacific, made its return in June 2026. Observations of sea surface height from the Sentinel-6 Michael Freilich satellite that month indicated that the 2026 event was continuing to strengthen.  

The natural, recurring phenomenon can have widespread effects, typically bringing wetter conditions to the U.S. Southwest and drought to countries in the western Pacific, such as Indonesia and Australia. NOAA declared an El Niño on June 11, after sea surface temperatures in the central and eastern equatorial Pacific measured at least 0.5 degrees Celsius above average for several consecutive months.

Meanwhile, NASA scientists have been observing a complementary sign of El Niño: areas of elevated sea surface height. When ocean water warms, it expands in volume and causes the sea surface to rise—making the water’s height a reliable indicator of ocean temperatures. Warmer-than-normal temperatures, hence higher sea surface heights, in parts of the equatorial Pacific Ocean are associated with El Niño.

The map above depicts sea surface height anomalies across the central and eastern Pacific Ocean as observed on June 8, 2026. Shades of red indicate sea levels that were higher than average. Normal sea level conditions appear white, and lower areas are blue.  

Data for the map were acquired by the Sentinel-6 Michael Freilich satellite—launched in 2020 by NASA and led by ESA (European Space Agency)—and processed by scientists at NASA’s Jet Propulsion Laboratory (JPL). Note that signals related to seasonal cycles and long-term trends have been removed to highlight sea level anomalies associated with El Niño and other short-term natural phenomena.

Earlier in spring 2026, the satellite started to detect precursor signs of El Niño as swells of warm water hundreds of miles wide, known as Kelvin waves, moved from the western Pacific to the eastern Pacific. That happens when trade winds in the western equatorial Pacific weaken and then temporarily reverse to blow from the west. Warm water piles up in the east, deepening the warm surface layer, lowering the thermocline, and suppressing the upwelling that usually keeps waters along the Pacific coasts of the Americas cooler.

This buildup of heat beneath the water’s surface is what sea surface height observations capture. It goes beyond surface temperature measurements to indicate how much heat is stored in the subsurface. That’s important because a shallow warm layer might not have much impact on climate and weather, while a large reservoir of heat below the surface can matter more.

According to JPL sea level researcher Severine Fournier, deputy project scientist for Sentinel-6 Michael Freilich, conditions in the western Pacific on June 8 looked similar to those from the same time in 1997, a year when an exceptionally strong El Niño emerged. Warm conditions in the eastern Pacific in 2026 have lagged behind, however, with fewer Kelvin waves built up by the same date.

Still, more warm Kelvin waves appeared to be approaching the eastern Pacific, meaning El Niño was still strengthening. Whether it catches up to 1997 depends on ocean activity in the coming weeks. “For now, it looks like it’s going to be a big one—more so than I would have said last week—but we still need more observations to know what’s going to happen.”

NASA Earth Observatory image by Lauren Dauphin, using modified Copernicus Sentinel data (2023) processed by the European Space Agency and further processed by Josh Willis, Severin Fournier, and Kevin Marlis/NASA/JPL-Caltech. Story by Kathryn Hansen.

Downloads

June 8, 2026

JPEG (1.19 MB)

References & Resources

• Climate Prediction Center/NCEP/NWS (2026, June 11) El Niño/Southern Oscillation (ENSO) Diagnostic Discussion. Accessed June 17, 2026.
• NASA Earth Observatory (2025, September 25) El Niño. Accessed June 17, 2026.
• NASA Earth Observatory (2023, June 21) El Niño Returns. Accessed June 17, 2026.
• NASA’s Jet Propulsion Laboratory (2026, May 27) NASA-European Sea Level Mission Homes in on El Niño. Accessed June 17, 2026.
• NOAA (2026, June 11) El Nino forms, expected to strengthen, say NOAA forecasters. Accessed June 17, 2026.

You may also be interested in:

Stay up-to-date with the latest content from NASA as we explore the universe and discover more about our home planet.

Barents Sea Tied to Low Arctic Sea Ice

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Patches of open water in the region contributed to low sea ice extent across the Arctic in March 2026, which…

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Editor’s Note: Today’s story is the answer to the June Puzzler.

The undulating landscape of north-central Nebraska may be easy to overlook among the iconic dune fields of the world. Far from any coast or desert, the Nebraska Sandhills—comprising the Western Hemisphere’s largest system of sand dunes—bring their own brand of beauty and value. Grasslands blanket the rolling hills, providing grazing grounds for livestock, while lakes and wetlands dot the landscape, supporting diverse plant and animal life.

Much of the sand forming the hills originated in the Rocky Mountains. Rivers carried the eroded material down from the mountains and deposited it across the Great Plains during the Pleistocene. In times of drought, winds blowing predominantly from the north or south lofted sand out of dried riverbeds, gradually building and shaping dunes. About 3,500 years ago, grassland vegetation stabilized the features. Today, the rippled pattern spans about 20,000 square miles (52,000 square kilometers), about one-quarter of the state of Nebraska.

Some of the largest dunes occur in and around the area shown in the detailed image above, near the northern edge of the Sandhills region. These transverse dunes stand as high as 400 feet (120 meters) and extend for several miles. Their northern slopes are gentler than their southern slopes, reflecting the dominant influence of northerly winds. In other areas, dunes are more symmetric, suggesting that winds blew with nearly equal strength from the north and south, alternating with the seasons.  

The grasslands that now cover the hills constitute pastureland for grazing livestock. Ranching expanded significantly in the area after passage of the Kinkaid Act in 1904, which allotted 640-acre parcels of land to ranchers who would settle it. Today, far more cattle than humans occupy the region, and half of Nebraska’s nearly 23 million acres of rangeland and pastureland are in the Sandhills. Some ranchers graze their cattle in patterns meant to approximate the large bison herds that once roamed the land.

Though much of the land in the Sandhills is privately owned, some is set aside in protected public lands. One of these areas, Crescent Lake National Wildlife Refuge on the southwestern edge of the Sandhills region, is shown above. Wetlands, including shallow lakes, marshes, and wet meadows, fill some of the valleys between the dunes. The land here is sponge-like, with precipitation seeping down through the soil and recharging groundwater instead of flowing off through stream channels.

Located along the Central Flyway, the refuge is a haven for migratory birds, and dozens of species of waterfowl, marsh birds, and shorebirds utilize the area. Among other wildlife, several types of turtles thrive in the ponds and prairies. Wetlands across the Sandhills support rare species such as the whooping crane, western prairie fringed orchid, and Topeka shiner.

NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.

Downloads

August 19, 2025

JPEG (10.71 MB)

References & Resources

• Nebraska Game and Parks, Sandhills wetlands. Accessed June 15, 2026.
• University of Nebraska–Lincoln (2024, October 23) Groundwater: How the High Plains Aquifer Shapes the Sandhills. Accessed June 15, 2026.
• University of Nebraska–Lincoln (2024, October 23) Rotational Grazing and Sustainable Grasslands. Accessed June 15, 2026.
• University of Nebraska–Lincoln (2024, October 23) What It Takes to Form a Giant Dune Field. Accessed June 15, 2026.
• U.S. Fish and Wildlife Service, Crescent Lake National Wildlife Refuge. Accessed June 15, 2026.
• USDA Forest Service, History of the Nebraska Sandhills. Accessed June 15, 2026.

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The post Nebraska’s Wide, Rolling Domain appeared first on NASA Science.

Editor’s Note: Today’s story is the answer to the June Puzzler.

The undulating landscape of north-central Nebraska may be easy to overlook among the iconic dune fields of the world. Far from any coast or desert, the Nebraska Sandhills—comprising the Western Hemisphere’s largest system of sand dunes—bring their own brand of beauty and value. Grasslands blanket the rolling hills, providing grazing grounds for livestock, while lakes and wetlands dot the landscape, supporting diverse plant and animal life.

Much of the sand forming the hills originated in the Rocky Mountains. Rivers carried the eroded material down from the mountains and deposited it across the Great Plains during the Pleistocene. In times of drought, winds blowing predominantly from the north or south lofted sand out of dried riverbeds, gradually building and shaping dunes. About 3,500 years ago, grassland vegetation stabilized the features. Today, the rippled pattern spans about 20,000 square miles (52,000 square kilometers), about one-quarter of the state of Nebraska.

Some of the largest dunes occur in and around the area shown in the detailed image above, near the northern edge of the Sandhills region. These transverse dunes stand as high as 400 feet (120 meters) and extend for several miles. Their northern slopes are gentler than their southern slopes, reflecting the dominant influence of northerly winds. In other areas, dunes are more symmetric, suggesting that winds blew with nearly equal strength from the north and south, alternating with the seasons.  

The grasslands that now cover the hills constitute pastureland for grazing livestock. Ranching expanded significantly in the area after passage of the Kinkaid Act in 1904, which allotted 640-acre parcels of land to ranchers who would settle it. Today, far more cattle than humans occupy the region, and half of Nebraska’s nearly 23 million acres of rangeland and pastureland are in the Sandhills. Some ranchers graze their cattle in patterns meant to approximate the large bison herds that once roamed the land.

Though much of the land in the Sandhills is privately owned, some is set aside in protected public lands. One of these areas, Crescent Lake National Wildlife Refuge on the southwestern edge of the Sandhills region, is shown above. Wetlands, including shallow lakes, marshes, and wet meadows, fill some of the valleys between the dunes. The land here is sponge-like, with precipitation seeping down through the soil and recharging groundwater instead of flowing off through stream channels.

Located along the Central Flyway, the refuge is a haven for migratory birds, and dozens of species of waterfowl, marsh birds, and shorebirds utilize the area. Among other wildlife, several types of turtles thrive in the ponds and prairies. Wetlands across the Sandhills support rare species such as the whooping crane, western prairie fringed orchid, and Topeka shiner.

NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.

Downloads

August 19, 2025

JPEG (10.71 MB)

References & Resources

• Nebraska Game and Parks, Sandhills wetlands. Accessed June 15, 2026.
• University of Nebraska–Lincoln (2024, October 23) Groundwater: How the High Plains Aquifer Shapes the Sandhills. Accessed June 15, 2026.
• University of Nebraska–Lincoln (2024, October 23) Rotational Grazing and Sustainable Grasslands. Accessed June 15, 2026.
• University of Nebraska–Lincoln (2024, October 23) What It Takes to Form a Giant Dune Field. Accessed June 15, 2026.
• U.S. Fish and Wildlife Service, Crescent Lake National Wildlife Refuge. Accessed June 15, 2026.
• USDA Forest Service, History of the Nebraska Sandhills. Accessed June 15, 2026.

You may also be interested in:

Stay up-to-date with the latest content from NASA as we explore the universe and discover more about our home planet.

Fires Tear Through Nebraska Grasslands

3 min read

Dry, warm, and windy conditions across the U.S. Great Plains led to extreme fire activity in March 2026.

Article

Farming in Ancient Lake Agassiz

3 min read

The glacial lake left a layer of silt and clay in southeastern Manitoba, creating fertile farmland that was divided during…

Article

America’s Emerald Isle

3 min read

Beaver Island is one in a string of verdant and scenic jewels in a northern Lake Michigan archipelago.

Article

Keep Exploring

Discover More from NASA Earth Science

Subscribe to Earth Observatory Newsletters

Subscribe to the Earth Observatory and get the Earth in your inbox.

Earth Observatory Image of the Day

NASA’s Earth Observatory brings you the Earth, every day, with in-depth stories and stunning imagery.

Explore Earth Science

Earth Science Data

Open access to NASA’s archive of Earth science data