At the start of the tour
Welcome to High Dune on First Ridge
Welcome to Great Sand Dunes National Park and Preserve, home of the tallest dunes in North America. The dunefield ahead of you covers about thirty square miles, and there are no trails in the sand, so everyone picks their own way.
Today we're hiking to the most popular spot in it: High Dune, on the first ridge. It's about a mile and a quarter each way. First we cross the wide, flat bed of Medano Creek, then we climb, zigzagging up along the ridgelines, close to seven hundred feet. We start at about eighty-two hundred feet above sea level, so go slowly and rest whenever you like. Most people take about two hours for the round trip, and up to four hours is normal if you're not used to the altitude.
On summer afternoons the sand can get hot enough to burn bare feet, and storms can bring lightning, so keep your shoes on, and if you hear thunder, head back to your car. This tour works without a signal. I'll tell you a story at a few spots on the way up and stay quiet in between, so you can listen to the dunes too.
Point 1 · At the stop
The view from the parking area
From this parking area, the first ridge of dunes rises in front of you, with the peaks of the Sangre de Cristo Mountains standing behind it. The dune that looks highest on that ridge is High Dune, where we're going. Here's a secret: it isn't the highest dune in the park, or the tallest. It only looks that way from this parking lot. But it does have a great view of the whole dunefield, and that's why so many people climb it.
So how did this much sand end up against a mountain range? The valley these dunes sit in, the San Luis Valley, is roughly the size of Connecticut. For hundreds of thousands of years, lakes and streams spread sand across its floor. When the water dried up, the wind took over. The main wind blows from the southwest, pushing the sand toward a low curve in these mountains, where the wind funnels toward three mountain passes and the sand piles up. Then, during storms, the wind turns around and blows back toward the valley. Pushed from both sides, the dunes have had nowhere to go but up.
History, on the way there
On the way: Medano Creek
Now for the creek bed under your feet. It belongs to Medano Creek, and the name comes from a Spanish word for sand dune, a fitting name for a stream that spends its whole life wrapped around one.
This creek, and Sand Creek on the north side of the dunefield, are a big part of why these dunes are so tall. Wind blows sand off the dunes and into the creeks. The water carries it back downstream to the valley floor, the wind picks it up there, and it blows right back into the dunes, so wind and water keep recycling the same sand, over and over.
Point 2 · At the stop
Medano Creek
In an average year, the creek first reaches this spot in April, at first just a trickle. Its peak comes in late May or early June, and that's when something rare happens here. Little dams of sand build up on the creek bed, hold back the water, then break, sending a wave down the creek about every twenty seconds. In wet years those waves can be a foot high. It's called surge flow, and this is one of the few places in the world you can see it. By July the creek has usually dried up near the parking area, so depending on the day, you may be wading or walking on dry sand.
Either way, there's water right below you. The dunes sit on top of an aquifer that reaches as much as a mile below the valley floor, and if you dig down a few inches almost anywhere in the dunes, at any time of year, you'll find damp sand.
Watch for dark streaks and swirls in the sand, too. That black sand is magnetite, an iron mineral heavier than the rest, sorted out by wind and water. A big patch of it can even spin a compass, but please leave it here for the next visitor.
History, on the way there
On the way: The foot of the dunes
Now for the people who knew this place first. Near the end of the last ice age, this valley was colder and wetter, with big wetlands and thick grass, and early hunters came here after mammoths and giant bison. At one ancient campsite in the park, excavated by the Smithsonian over fifteen years, at least forty-nine bison had been trapped against a small dune. Several families worked together there for about a week, drying the meat, making new stone points and making clothing.
The dunes still matter to many tribes today. In the Ute language, the name for this place means where the sand is. The Jicarilla Apache name means it goes up and down, and the Navajo name means sand comes back down on you, which anyone who has climbed a dune will understand.
Point 3 · At the stop
The foot of the dunes
About here, the flat creek bed gives way and the sand starts to rise. The park says this is the place to look for classic barchan dunes, the small dunes right across from the main parking area, at the foot of the tall ones. A barchan is a simple crescent with two arms pointing forward. The name comes from an Arabic word for horns, and they form where the wind blows from just one direction and almost nothing grows. Dunes move, so they may not sit exactly where they did last year.
A few things before we climb. If you have kids with you, don't let them dig deep holes at the foot of a steep dune, because once in a while the slope can collapse into the hole. From here on the hike gets harder, and the trick is to zigzag along the ridgelines instead of charging straight up the steep faces. Take as many breaks as you need along the way.
Point 4 · At the stop
Climbing the ridges
By now you're climbing along the dune ridges, and the sharp crests around you are the most common kind of dune in the park. Most of this dunefield is made of reversing dunes. The main wind, from the southwest, pushes the sand toward the mountains. Then storm winds come off the mountains from the northeast and flip the top of each dune back the other way, and that tug of war leaves these sharp ridges.
Listen, too. When sand slides down a steep dune face, millions of tumbling grains can make a deep hum, a little like a voice. It happens on its own during storms, and people can start it by pushing sand down a slope. Back in the 1940s, Bing Crosby even had a hit song called The Singing Sands of Alamosa.
Up here there's less oxygen than most of us are used to. If you get a headache or feel short of breath, slow down, drink some water and give your body time to adjust.
History, on the way there
On the way: High Dune
Now for how this place came to be protected. In the 1920s, gold was found in these dunes, and miners began working the sand. Valley residents worried for the dunes' future, and a group of local women from the P.E.O. Sisterhood took up the cause. Led by Elizabeth Spencer, they ran a letter-writing campaign that reached all the way to Washington, and on March 17, 1932, President Herbert Hoover proclaimed Great Sand Dunes National Monument.
Nearly seventy years later, the threat was water, as companies hoped to pump groundwater from beneath the valley and pipe it to fast-growing cities on the Front Range. Again, valley residents banded together. Congress passed a law in 2000 to turn the monument into a national park and preserve, a huge ranch on the dunes' northwest side was bought from willing sellers in 2004, and that September, this became a national park.
Point 5 · At the stop
High Dune
You made it. This is High Dune, on the first ridge, close to seven hundred feet above its base, and from up here you can see why it's the most popular destination in the dunefield. The whole dunefield spreads out around you, ridge after ridge of sand. If you can pick out a pyramid-shaped dune rising above the others, that's Star Dune, at seven hundred and thirty-six feet the second tallest in North America. The tallest, Hidden Dune, at seven hundred and forty-one feet, lives up to its name, out of sight from much of this ridge.
And here's a surprise: all this sand is only about a tenth of the whole deposit. Almost ninety percent of it lies in the sandy grasslands that surround the dunefield on three sides, and that's where most of these dunes' sand comes from. The photographer William Henry Jackson photographed this first ridge in 1873, and a photo taken from the same spot in 2020 looks remarkably alike.
When you're ready, head back down the way you came, at your own pace. Thanks for hiking to High Dune with me. If you can, come back after dark, because this is an International Dark Sky Park, and the stars over these dunes are something you won't forget.