With the walls closing in at home, my family and I decided to head out to the Alvord Desert for some much needed solitude and wide-open space for a weekend in mid-May. The plan was to camp for a couple nights, and hike and explore during the day. The Alvord Desert is on BLM land and primitive camping is allowed. So, with the promise of room to roam, we packed up our vehicle with the necessary provisions, loaded up the car, and headed southeast.
Alive in the Alvord
The Alvord Desert is a playa located on the east side of Steens Mountain- a huge fault block mountain that runs for miles at the edge of Oregon’s Basin and Range region. Dry and expansive (about 11 miles long and 6 miles wide), with a cracked earthen floor. The Alvord Desert landscape feels alien- devoid of greenery and seemingly lifeless; a monotonous swath of dirt and dust. Much like what you would expect from a desert.
But then…
You watch the sun rise and fall, casting shadows and painting the sky intermittently between hours of moon and stars and wind. You roam the sagebrush boundary lands, hunting for lizards or other desert life. When the sun is high and the heat is too much, you swat away invertebrates while reading the book you brought on the trip, moving every once in a while in order to remain in the shade. On your early morning run, you discover large pools of water that make you reflect on what you know about hydrology (more on that later). And suddenly, you find yourself waxing poetic about this mysterious landscape called the Alvord Desert… Or maybe it is just me.
Arrival
After driving for countless miles, my family and I arrived in Alvord Desert late in the afternoon. It was finally cooling down for the night, when we found a spot to camp on the edge of the playa. There, we spent the evening watching our shadows grow long and once night hit, we counted stars and waited for the moon to rise. Eventually, one-by-one, we fell asleep to the sound of the desert winds, visions of wide-open-spaces dancing in our heads.
The Hike or Run
- Trailhead: any place you can find your way back to (make sure you know your return coordinates)
- Distance: any distance your energy level will allow
- Elevation Gain: virtually none
- Notes: Run or hike from virtually any point you would like. Bring plenty of water. Distances appear shorter in the desert, so plan accordingly. Make sure you know where you are starting from, so you can make it back safely.
A Glass Half Full
At first light, I was up and ready to explore. My plan from the get-go was to run the playa: so much space and nearly level ground- a distance runners dream, I thought. So I donned my running gear and started to move. The light of the early morning was magic, as I trotted along at my usual slow pace, soaking in the atmosphere. I followed the shrub-lined edge of the playa for most of the run. It was eerie and peaceful.
Eventually, I made it around to the opposite side from camp and figured I would cut across the playa when- splash- water! What I had thought was a desert mirage, was actually a thin lake of water that made crossing the playa at that point impossible.
Rerouting my run, questions began to soar through my mind about the wet encounter. I had read that the Alvord desert had a wet and dry season, but for some reason it didn’t fully register until that moment; until I ran smack into it.
Tired and a bit dehydrated from my run, I thought a lot about the hydrological cycle of the Alvord- about its cycles and seasons- and decided I needed to know more about this unique land of wet mud and dry dust.
Ready? Let’s Playa in the Alvord!
In the Shadow
Lying within the rain shadow of Steens, the Alvord Desert is considered the driest place in the State of Oregon, receiving only about 7 inches of precipitation per year. As part of Oregon’s interior, not a lot of moisture makes it to this southeastern region. And what little does makes it into the region, is removed from the atmosphere as snowfall on Steens Mountain’s western flank. This process is known as the rain shadow effect. When moisture laden air travels up a mountainside (the windward side), it cools, condenses, and eventually falls as precipitation. The dry air then continues down the other side of the mountain (the leeward side), where it heats up, encouraging further drying through evaporation. The Alvord Desert is on the leeward side of Steens, so it not only gets little rainfall, but it experiences a lot of evaporation.
Dry and Cracked
Additionally, the Alvord basin, like most watershed in the Basin and Range of Oregon, is a closed-watershed system. Instead of taking a more traditional route to the Ocean, water in the Alvord doesn’t leave by surface or groundwater flowing to the Ocean. Instead, it stays in the basin until the hot sun evaporates it away. The result is another interesting features of the Alvord- cracks.
Alvord Desert’s surface is riddled with geometric shapes separated by cracks. Known as desiccation fractures, these cracks form as the surface of moist clay-rich sediments dry and shrink through sun and wind evaporation. Shrinking results in tensile stresses that radiate out in all directions on the surface that ultimately break, resulting in polygonal cracks- one of the Alvord Desert’s characteristic features.
Reflecting on a Thin Film of Water
O.K. so that explains why it is so very dry in the Alvord Desert, but it doesn’t explain why there is water there at all. Where does the water come from, if not from precipitation?
Perhaps not surprisingly, much of the water in the Alvord Desert comes from higher up- on Steens Mountain. Steens Mountain captures a lot of precipitation in the form of snow. Later in spring, the snowpack melts and feeds streams and groundwater systems that supply water to the basin below. Much like how water accumulates in the drain at the bottom of your sink, the Alvord Desert is one of several low points, separated by alluvial divides, that capture water draining from Steens above.
Shifting Waters
However, as a desert playa, the Alvord Desert also happens to be very large and very flat. In the spring, expansive areas fill with water but at a depth of only a few centimeters. It is the process of inundation that actually helps maintain the flatness of a playa- laying down sediments evenly throughout.
When visiting the Alvord Desert it is important to remember that these thin, but massive lakes of water may grow or shrink, and/or shift, making parts of the playa potentially impassable at times. During my morning run on the playa, it was just a matter of rerouting, but there is potential for getting stranded by these shifting waters. In the Spring, when water levels are wide, the risk of getting trapped by pooling water is particular high, so plan accordingly.
An Ancient Lake
However, even during its wettest season, the thin surface water of the Alvord is nothing compared to the amount of water it once held during its tumultuous past. From about 3.5 million years ago to 15,000 years ago, recurring ice ages increased rainfall in southeast Oregon that filled the large basins characteristic of the region. The Alvord Desert and surrounding sub-basins (as far south as Nevada) were all connected as one massive pluvial lake. Filled to the brim, Pleistocene Lake Alvord had a depth of nearly 200 feet at one point, and would often overflow.
Overflowing
During periods of overflow, water would travel via Crooked Creek to the Owyhee River. During one cataclysmic event, water burst through Big Sand Gap on the lake’s eastern rim, eroding it down about 12 m, and sending torrents of water into the much smaller Pluvial Lake Coyote, through Crooked Creek, and out to the Owyhee River. Today along Crooked Creek, you can observe the scabland terrain and boulder bars that serve as evidence of this event. Apparently, you can also hike out to Big Sand Gap from the Alvord Desert by following wild horse trails to see the breach up close- something I will have to try on my next trip.
It wasn’t until the last 10,000 years that the Earth warmed again and the Alvord became the desert you see today.
You Should Go Playa
Whether you explore on foot or otherwise, the Alvord Desert is a magical place to visit. It may look one-dimensional at first glance, but if you stay awhile, the dynamic nature of the landscape, with it’s subtle shifts and movement, begin to unfold. You should seriously go “playa” in the Alvord- you won’t be disappointing. Just don’t forget the moisturizer.
- “Alvord Desert – The Oregon Encyclopedia.” 20 Mar. 2018, https://oregonencyclopedia.org/articles/alvord_desert/. Accessed 26 May. 2020.
- “Playa | geology | Britannica.” https://www.britannica.com/science/playa. Accessed 26 May. 2020.
- Tanner P.W.G. (1978) Desiccation structures (mud cracks, etc.). In: Middleton G.V., Church M.J., Coniglio M., Hardie L.A., Longstaffe F.J. (eds) Encyclopedia of Sediments and Sedimentary Rocks. Encyclopedia of Earth Sciences Series. Springer, Dordrecht.
- O’Connor, Jim E., Rebecca J. Dorsey, and Ian Madin, eds. Volcanoes to vineyards: geologic field trips through the dynamic landscape of the Pacific Northwest. Vol. 15. Geological Society of America, 2009.
- “Oregon: A Geologic History – Oregon Geologic Timeline.” https://www.oregongeology.org/pubs/ims/ims-028/timeline.htm. Accessed 26 May. 2020.