Even though the dunes can be seen from miles away, driving up to the Great Sand Dunes National Park in south central Colorado is still a surreal experience. Typically, when there is this much sand, there is an ocean nearby, but all there is here are the 14,000-foot peaks of the Sangre de Cristo Mountains to the east and the open San Luis Valley to the west. The tallest sand dunes in North America are found at Great Sand Dunes National Park, reaching heights of 750 feet. While that may not sound very high to a seasoned hiker, remember that this is sand, not solid dirt!
While scientists aren’t completely sure, it’s generally accepted that the dunes started forming around 440,000 years ago when Lake Alamosa, which once covered most of the San Luis Valley, receded and drained through volcanic deposits to the Rio Grande River. Once the water was gone, the southwest winds blew the remaining sand into the natural curve of the Sangre de Cristo Mountains. During storms, winds come from the east through the Mosca, Medano, and Music Passes, and these opposing wind forces continue to build the dunes higher and higher. There are also two streams in the area—Medano and Sand Creeks—that bring water and sand down from the mountains to the valley floor. When the creeks disperse or dry up, that sand is also blown into the dunes.
Just because the dunes are in a windy, high altitude desert, don’t think there isn’t life here! The first few inches of the dunes are dry and experience extreme temperatures, but just below the surface, there is enough moisture for species such as Ord's kangaroo rat, Great Sand Dunes Tiger Beetle, scurfpea, and blowout grass to survive. Other animals visit the dunes, too, such as elk, pronghorn, bison, coyotes, bobcats, and raptors.
The area was designated as Great Sand Dunes National Monument in 1932, and became a national park in 2004. The park has several ecosystems and habitats, ranging from grasslands and shrublands on three sides of the dunefield to high alpine tundra to forests and meadows to alpine tundra up in the mountains.
Just about everyone comes to the park to explore the sand dunes. The dunefield is 30 square miles, and there are no set trails. There are five dunes over 700 feet, but the High Dune (at 699 feet) is the most popular one in the park. It looks the tallest from the parking lot, and will give visitors a wonderful scenic view of the dunes and the surrounding landscape. The average time to hike this dune is about two hours.
From High Dune, look west to see Star Dune, the highest in North America. Traverse about a mile and a half up and down other dunes to get to the peak. Expect about five hours roundtrip to the top of Star Dune and back.
Besides hiking, many visitors enjoy sandboarding or sledding down the dunes. Regular snowboards, sleds, or plastic trashcan lids won’t work (you’ll likely just get stuck in the sand), so head to one of the two places to rent a sandboard or sandsled—year round at Kristi Mountain Sports in Alamosa, or from April to October, at the Oasis Store outside the park entrance.
But it’s not all about the sand dunes! With the Sangre de Cristo Mountains right there, it’s no surprise that there are some worthwhile alpine trails, too. The Mosca Pass trail is a great one on a hot day, as it winds up through aspen and evergreen to a pass in the mountains. The trail is seven miles roundtrip, and follows a route once traveled by Native Americans and early settlers to get in and out of the valley.
For a real challenge, summit 13,297' Mount Herard for a breathtaking view of the mountains and the dunes. It’s about a 10-mile roundtrip and requires 4WD to get to the trailhead. Pick up a copy of The Essential Guide to Great Sand Dunes National Park and Preserve at the Visitor Center bookstore for more information and directions to the trailheads in the area.
After a long summer day on the dunes or the trails, head to Medano Creek (at the base of the dunes) for a fun float or just a little splash to cool off. The best water flow is in April and May, and visitors can also skimboard on the creek.
Secrets of the Park
If you have a 4WD vehicle, drive up to the Eastern Ridge and take a break at the Sand Pit or Castle Creek Picnic Areas. There is a tall, steep dune face at Castle Creek, and both spots are near Medano Creek.
Colorado is well known for its vibrant fall colors, especially when the aspens burst into hues of gold and orange. One of the best places in the state to see fall foliage is through Medano Pass. The road requires a high-clearance 4WD vehicle and is only passable in warmer months, so not many people venture up there. There is camping along the 22-mile primitive road, many creek crossings, and some sand to get over. Check conditions before you go.
Medano Creek is one of the only places in the world where visitors can experience the phenomenon known as “surge flow”, which only happens when there is just the right balance of water, sand, and slope. This usually occurs in the spring or early summer when the water flow is at its peak, and visitors will see waves rolling in about every 20 seconds. Sometimes, they can get up to foot high, making skimboarding or floating even more fun.
Great Sand Dunes National Park is just over 30 minutes from the nearest town of Alamosa, so it’s easy to get a hotel room if you want to spend a weekend exploring the dunes. There are also some campgrounds at the park, but no matter where you stay, it’s definitely worth spending a couple days here—one day to explore the dunes, and another day to hit the trails in the mountains.
How to Get the Most Out of Your Visit
- The area is very windy. Bring eyewear (sunglasses should be fine) and a handkerchief or something to protect your face just in case the winds are really strong (winds can get up to 40 miles an hour).
- You can visit the dunes year round, but if you come in the summer, the park is really busy, so weekdays are best. Also in the summer, the dunes get to 150 degrees, so go out in the early morning or later evening. Spring and fall are the best times to visit.
- Medano Creek has the best flow in late May. In June, the mosquitos come out, so the creek can get quite buggy.