Sunday, August 2, 2015

Great Sand Dunes National Park

We have now moved from Colorado Springs to Alamosa, Colorado.  We are still seeing mountains here in the San Luis Valley.  San Juan Mountains and Continental Divide are to the West, and thirty miles south, beyond the San Juan Hills, is New Mexico.  The Sangre de Cristo Mountains enclose the Valley to the East and north.  They provide a dramatic back-drop to the Great Sand Dunes.  In the picture below the dunes are the thin white strip below the mountains.  In the foreground is a very arid valley.
Thirty square miles of the dunes stretch to the north, south and west.  According to a park brochure, the dunes were formed thousands of years ago with sand and and sediment which washed down from both the San Juan as well as Sangre de Cristo mountain ranges.  Prevailing southwesterly winds bounced the sand grains to pile them up beneath the Sangre de Cristo Mountains.  Prevailing northeasterly winds through the mountain passes caused the sand to pile back up on themselves thus creating very large dunes.  They are the largest in North America, some as high as 750 feet.
We hiked up to the nearest hill of dunes, it was a hard climb, and we felt it necessary to move fast as a storm was moving in.  Climbing those hills was a lot harder than we had imagined, but it was fun running down-I did not care at all if I fell!  Most fortunately it was overcast and cool.  During the summer months the sand can be as hot as 150 degrees F.  

It is necessary to cross a creek bed before climbing the dunes.  Medano and Sand Creeks wrap their arms around the dunes.  The creeks are fed by melting snow from the mountains during the spring months, which resupply the aquifers below the dunes.  By August the creeks are just small puddles, as seen in the picture above.  What is fascinating about the dunes is that they are constantly changing color due to the play of sun rays and shadows on them.  While we were in the area we saw them change from brown to gray to pink and white.  Clouds above us also were ever changing, from fluffy white to dark rain clouds. It never rained that hard on us, but off in the distance we could tell that the rain was pouring down.
One last item here.  While hiking around the visitor's center I came upon the most exquisite plant with pale pink blooms on it.  I learned from a park ranger that it is a desert verbena.  According to him, what I thought of as flowers on it were instead the fruit or seeds of the plant.

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