Mountains of Sand

Sunset over the Great Sand Dunes. Note the sunlight catching the thin layer of sand being blown across the surface, no more than a few inches above the ground. Saltation in action!

I’ve been to my fair share of sand dunes; St. Anthony Dunes and Bruneau Dunes in Idaho, Oregon Dunes on the Pacific Coast, Coral Pink Sand Dunes in southern Utah, Juniper Dunes near Walla Walla, and a handful of dunes in New Zealand that I don’t remember how to pronounce much less spell.  By comparison though, the Great Sand Dunes in south-central Colorado truly deserve their title. In fact, one feels somewhat uncomfortable using the term “dune” due to its complete and total inability to convey the grandiose scale of this geological wonder. A weary traveler approaching them might be liable to exclaim “That’s no dune!” (if you didn’t catch that cleverly placed Star Wars pun, you should watch this short video clip immediately) upon the realization that these are no ordinary dunes.  No, they are perhaps better described as a small mountain range made of sand. When one first looks upon the dunes, it seems inconceivable that the entire massif could be made of sand. After slogging my way to their summit though, I assure you that they are.

Approaching the dunes from the south…Sangre de Cristo Mountains in the background.

Before beginning to ascend the dunes, one must first cross Medano Creek, a small stream originating in the Sangre de Cristo Mountains that flows between the mountains and the dunes. Due to the abnormally low snowfall in the Colorado mountains this past winter, by the time I visited in mid-June, this was a non-issue. The creek was only a few inches deep and therefore easily traversed.  Medano Creek is nevertheless just one of many features that makes the Great Sand Dunes stand out from their sand dune brethren around the world. The presence of a reasonably reliable water source along the base of the dunes creates a beach-like environment that, judging by the number of families with small children, is very conducive to building sand-castles.

Medano Creek meanders its way across the sand flats

The hike up to High Dune (which confusingly is NOT the highest dune; that title belongs to nearby Star Dune which is about 100 feet higher) is well-traveled yet there is no official trail so everyone ends up taking a slightly different route making it difficult to find footprint-free sand for good photographs. Hike past High Dune though and you are almost immediately alone in the midst of many, many square miles of untrodden, pristine, windblown sand. Anyone who has ever hiked up a sand dune before knows that you have to expend quite a bit of energy to extract your sinking foot from the sand after each step.  The somewhat demoralizing thing about hiking through sand dunes is that what takes you an hour to hike up, you can run down in less than a minute. Given that the running down part is thoroughly enjoyable; hiking the sand dunes is, in a way, analogous to waiting in line at Disneyland for two and half hours in order to go on Splash Mountain for two minutes. The analogy fails in that Splash Mountain doesn’t leave you picking sand out of every part of your body for the next three months and you don’t get an on-ride photo running down the sand dunes.  However, even hiking up the dunes, while difficult, is still a very enjoyable experience.

A lone hiker trudging up a small foredune on the way to High Dune provides an excellent sense of scale

Hikers cross the final ridge to High Dune underneath a 3rd quarter Moon

Wow, I’ve written three entire paragraphs without even MENTIONING geology yet!  This must stop now before they make me give my degree back. Anyhoo, most of the sand originates in the San Juan Mountains to the west, is transported to the edge of the vast San Luis Valley and then blown eastward by prevailing winds for many miles before the sand slams into the Sangre de Cristo Mountains and accumulates in a ginormous pile at their base. The color of the sand is a bit difficult to describe. During the day, it appears slightly off-white, cream, or ivory you might even say. However look at the sand closely and you’ll see that it consists of many orange to pink to yellow colored grains; colors which are brought out in all their glory at sunset.  In a few spots on my hike/run down the dunes, the innards of the dunes were visible, exposing the intricate bedding pattern that results from sand being blown up the shallow side of the dune and then cascading down the slipface.

A series of 1-m scale sand avalanches slide down a steep slipface

A rare outcrop of sand reveals the layering that underlies the sand dunes

Sunset in the dunes was one of the most indescribable experiences I’ve ever…umm…experienced. Never mind that positioning yourself correctly on the dunes allows you to watch the sunset half a dozen times if you start at the top and slowly move your way downhill, the colors and patterns in the dunes brought out by the Sun setting through the smoke and haze in the western sky (much of it regrettably emanating from wildfires in New Mexico fires)  were spectacular. The low angle of the sun revealed the small-scale dunes that are ubiquitous yet nearly invisible in the harsh mid-day lighting (see photo at top of page).

Looking north towards the Sangre de Cristo Mountains at sunset.

Walking along the dune crests at sunset.

Since this has already ballooned to one of my longer entries, let’s go ahead and make this Part 1 of 2. The dunes are just one of many attractions in the San Luis Valley/Sangre de Cristo region. The other attractions that I will detail soon may or may not include an alligator farm…

And that my friends, is called a “cliffhanger.”