30 square miles and up to 700 feet tall.
They are roughly five miles wide in circumference and about 700 ft tall.
Last I heard the tallest sand dune was 700 ft. And yes, they are the tallest in North America.
The Sand Dunes are largest in USA I believe. There is a seasonal creek that flows in front of Dunes due to mostly snow melt. I have seen other Day es in the USA and these are tallest I've seen
This is my first time seeing sand dunes. I thought they were huge. They looked like foot hills to the mountains. People were climbing them with boards, that looked like snow boards, and then riding down. There is also a river in front of the dunes where people were playing!
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