Fall Colors of the Rio Grande

There will always be pockets of beautiful fall color to be found in the mountains and foothills that surround the San Luis Valley and along the Rio Grande and Conejos Rivers.  Generally, the aspen begin to change up river of Wagon Wheel Gap about a week before the mountains that surround the San Luis Valley.  And the aspen in Chama Basin will often turn a week later than those around the valley. 

Aspen aren’t the only colorful show in the autumn.  Rust colored Gambel oak mix in with the lower elevation aspen in the northern part of the San Luis Valley, while all the foothills include a plethora of multi-hued shrubs.  Additionally, the leaves of many of the summer wildflowers will turn a variety of colors ranging from dull maroon to vibrant yellows and oranges.  In other words, if you don’t get stuck on looking just for aspen, you can find spectacular fall color no matter where you go in the foothills and mountains of the upper Rio Grande.

Fall Color Updates & Photo Albums - Cottonwoods in the lower elevations still have some leaves. Trees at higher elevations have mostly lost their leaves.

Conejos Peak District     2013 Photos   2015 Photos

Divide District                 2013 photos    2014 photos   2015 photos

Saguache District            2013 photos   2014 photos  2015 photos


Region 2 fall color information

Why do leaves change color? In the Autumn, the decrease in the intensity and duration of sunlight, as well as cooler temperatures, causes the leaves to stop their food-making process (photosynthesis). The chlorophyll in the leaves breaks down, causing the green color to disappear, and the yellowish pigments, known as carotenoids, become visible. The Autumn foliage of some trees, including aspen, birch and ash, are mostly yellowish colors. The reddish pigments, the anthocyanins, become more visible in the leaf veins and cells in some leaves, such as maples.

Leaves have just as much yellow pigment (xanthophyll) in July when they are green as they do in October when they are yellow. In July the darker green pigment (chlorophyll) masks the yellow color. More info on color changes.

For more information about Fall colors check out these websites: