Great Sand Dunes National Park's Tallest Dunes Shrinking

Great Sand Dunes National Park's Tallest Dunes Shrinking

Four or five of the mega dunes towering over Colorado's San Luis Valley appear to be shrinking, according to Andrew Valdez, the geologist at Great Sand Dunes National Park and Preserve who has tracked the dunefield for more than 30 years. Star Dune, long known as North America's tallest, now measures approaching 720 feet, down almost 40 feet from where it stood in 2000. High Dune has followed a similar pattern, generally dropping in height even …