EarthWatch: Sand Dunes in Alaska

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Dune fields stand out in the Kobuk Valley amid a green backdrop. 

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Produced by the Space Telescope Science Institute‚Äôs Office of Public Outreach in collaboration with the NASA Earth Observatory: https://earthobservatory.nasa.gov/  

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Text, Earth Watch, Exploring the Blue Planet by Satellite
 
An aerial view of sand dunes in Alaska on August 16, 2020
 
Text, Within Kobuk Valley National Park in northwestern Alaska, two treeless stretches of sand stand out against the dark green forest.
 
These sand dunes rise as high as 30 meters (100 feet).
 
Winds still sculpt roughly 25 square miles (65 square kilometers) of these dune fields.
 
The sand that makes up the dunes owes its existence to the movement of glacial ice.
 
During the last ice age, massive sheets of ice moved slowly over mountains and other rocky surfaces, grinding the bedrock into fine sediment.
 
Over time, sand and silt were carried by streams and wind, and deposited in the ice-free Kobuk Valley.
 
These sand dunes continue to shift with the wind, but very slowly since they are in a cold climate and are often covered by ice and snow.
 
These dunes are highlights of Kobuk Valley National Park, which is one of the most remote sites in the U.S. national park system.
 
Although hundreds of thousands of caribou migrate through the park each year, fewer than 20,000 humans visit annually.
 
To learn more, go to: earth observatory dot nasa dot gov