Hiking Trails in Valles Caldera National Preserve, Revised Edition

By Coco Rae and Tom Ribe

Avid hiker Coco Rae shares her extensive knowledge and her love of exploration at one of New Mexico’s greatest treasures in this updated and expanded edition of Hiking Trails in Valles Caldera National Preserve. The first comprehensive trail guide to Valles Caldera National Preserve now includes over seventy color photographs and everything visitors need to know to enjoy this vast caldera, one of the largest in the United States. The guide includes detailed descriptions of over twenty-five trails accompanied by topographical maps, recommendations for mountain bikers, and a history of the preserve.

A geological and environmental wonder created over a million years ago, Valles Caldera National Preserve, west of Los Alamos, New Mexico, offers outdoor enthusiasts and nature lovers endless opportunities to discover the natural history of New Mexico through the caldera’s vast mountain meadows, extensive biodiversity, and meandering streams. Hiking Trails in Valles Caldera National Preserve offers first-time and returning visitors a complete guide to the recreation and beauty found in this unique landscape.

• Language: English
• Publisher: University of New Mexico Press
• Release date: Apr 1, 2022
• ISBN: 9780826363619

Coco Rae

Coco Rae is a volunteer at Valles Caldera National Preserve who has been hiking in northern New Mexico for over twenty years. She lives in Los Alamos, New Mexico, with her husband.

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Accessing Valles Caldera National Preserve

Accessing Valles Caldera National Preserve

Valles Caldera National Preserve is located near mile marker 39 on the north side of NM 4 in Sandoval County, about 30 minutes west of Los Alamos. The map on page 2 illustrates the backcountry access roads, along which most trailheads are located. The trailheads for Coyote Call & Rabbit Ridge Trails, Banco Bonito Loop (VC07), and Redondo Creek–Mirror Pond Trail (VC02) are accessed directly from NM 4. The trailhead for Sulfur & Alamo Canyons Loop and Redondo Border Trail (VC08) is accessed from Forest Road 105, which is near mile marker 27 on NM 4. It takes about 90 minutes to reach VCNP from either Santa Fe or Albuquerque, depending on traffic and weather conditions.

Driving directions from Santa Fe: Take US 84/285 north to Pojoaque and turn left (west) onto NM 502. Take NM 502 to the exit for NM 4 and follow the signs for Bandelier National Monument and White Rock. At the stoplight at the T-junction, turn right (west) to take NM 501/East Jemez Road (the Los Alamos truck route) up the hill. At the stoplight at the top of the hill, turn left (south) to pass through the security checkpoint at Los Alamos National Laboratory (LANL). This generally only requires you to show your driver’s license, and is necessary because the road passes through LANL property. Follow the signs along NM 501 as it passes through the laboratory and turns south, reaching a T-junction with NM 4. Turn right (west) onto NM 4 and head up the mountain, reaching the entrance gate for VCNP after about 10 miles.

If you do not wish to pass through the LANL security checkpoint, instead of taking NM 501/East Jemez Road up the hill, continue on NM 4 through White Rock, following the signs for Bandelier National Monument. Continue past the entrance to Bandelier, taking NM 4 all the way to VCNP. This route is slightly longer but avoids the checkpoint.

Driving directions from Albuquerque: Take I-25 north to Bernalillo to the exit for US 550. Turn left (west) onto US 550 and take it north to San Ysidro. At San Ysidro, turn right (northeast) onto NM 4. Follow NM 4 as it heads up the mountain, reaching the entrance gate for VCNP after about 39 miles.

A Brief History of Valles Caldera National Preserve

Valles Caldera National Preserve is one of the newest of the protected lands within the National Park System, yet its landscape reflects a political history of centuries, a cultural history of thousands of years, and a geological history of millions of years. In its past we may see traces of Spain’s New World empire, Mexico’s fight for independence, America’s westward expansion, and New Mexico’s integration into the United States. One may also see the long and rich history of Native American life and culture in the Southwest and its extensive ties to far-flung Indigenous communities across North America. And of course, the geological forces that shaped the landscape as we know it today may be read in the hills and valleys that make up this unique and special place.

The geological history of VCNP has been a source of fascination for thousands of visitors, and it has established the caldera as a must-see destination for professional and amateur geologists from all over the world. Indeed, Fraser Goff (2009), one of the leading experts on the caldera’s geology, has noted that it is the world’s best example of a resurgent caldera, having been identified as a caldera in the 1920s by C. S. Ross of the United States Geological Survey. The caldera is so well defined that in the 1960s, geologists R. L. Smith and R. A. Bailey decided to use its characteristics to define all calderas worldwide (Goff 2009). The preserve sits atop the junction of two major geological features of the Southwest: the Jemez Lineament, which runs southwest to northeast across New Mexico, and the Rio Grande Rift, which runs north to south down the middle of the state. The Jemez Lineament is easy to see on a map of the Southwest. Its presence may be traced from Arizona’s White Mountains in the southwest, across the caldera, and up to Capulin Volcano in the Raton–Clayton volcanic field in the northeast corner of New Mexico. Similarly, the Rio Grande Rift is marked by the famous river that flows down it. For millions of years, these tectonic features have produced a wide variety of volcanic activity, perhaps the most spectacular being the two major eruptions that created the caldera.

When viewed from above, the caldera is slightly oval in appearance, rather than more perfectly round; this is because the first major eruption, which created the Toledo Caldera around 1.6 million years ago, was nearly obliterated by the second eruption, which created the current caldera rim around 1.25 million years ago (Goff 2009). Caldera formation may be understood as something like a magma-filled soufflé: As rifts pull apart and temperatures and pressures rise, the land is forced upward by the rising magma, until the pressure becomes so great that an eruption occurs, scattering volcanic material everywhere. When the pressure is released and the magma is spent, what material remains collapses and the center drops lower than its original surface, filling the void left behind by the erupting lava. The Toledo Caldera was approximately 9 miles in diameter. It developed after producing an eruption column nearly 20 miles high, pyroclastic flows of 50–200 miles per hour and at least 950° F, and 85 cubic miles of volcanic material that reached as far as what is now Kansas (Goff 2009). Within about 400,000 years of the Toledo Caldera eruption, the first lava dome, Rabbit Mountain, formed along the southern rim. A lava dome is formed by a secondary, lesser eruption, whereby magma rises to the surface and erupts as lava, which subsequently hardens to form a volcanic dome.

The second major eruption, which created the rim of the caldera as we know it today, produced slightly less volcanic material, yielding about 75 cubic miles of ash flow and scattering it nearly as far as the Toledo eruption (Goff 2009). For comparison, the famous 1980 eruption of Mount St. Helens only yielded 0.7 cubic miles of debris. However, although both eruptions were impressive, despite popular belief the caldera is not a supervolcano, the definition of which requires over 240 cubic miles of debris. The resultant oval ring produced by the second eruption is about 12–15 miles in diameter, depending on where it is measured. Of the three large Quaternary period calderas (2.58 million years ago to today) in the United States—Yellowstone in Wyoming, Long Valley in California, and Valles Caldera—Valles Caldera is the oldest and the smallest (Goff 2009). The ash deposits of the first eruption are known as Lower Bandelier Tuff, and the ash deposits of the second eruption are known as Upper Bandelier Tuff. Both of these layers may be seen in the mesas of the nearby Pajarito and Jemez Plateaus, and it is out of Upper Bandelier Tuff that the ancient Pueblo peoples enlarged air pockets into cave dwellings and ultimately expanded into the built structures that may be seen at nearby Bandelier National Monument.

Satellite image of Valles Caldera. Photo by NASA Earth Observatory.

Soon after the second eruption the valley floor began to rise again, and in the incredibly brief period of about 30,000 years, Redondo Mountain was formed at a rate of about 1 inch per year. Goff (2009) notes that, had people been living in the area at the time, this rate was fast enough to have been noticeable. This is the highest of the mountains within the caldera, reaching 11,254 feet, which is roughly the height of the highest point before the original eruption. Redondo Mountain is the only resurgent dome in the preserve, which means the magma forced the surface upward but did not actually erupt. After Redondo Mountain formed, a series of further eruptions occurred over about 750,000 years, forming lava domes starting with Cerro del Medio around 1.23 million years ago, and erupting roughly counterclockwise one by one until San Antonio Mountain was formed around 560,000 years ago. Cerro La Jara, the tiny dome adjacent to the VCNP Entrance Station, and South Mountain, just to the north of it, were both formed around 520,000 years ago. The El Cajete formation occurred around 55,000 years ago, and the Banco Bonito formation is the youngest in the preserve, having developed around 40,000 years ago (Goff 2009). As these lava domes formed, they filled in the floor of the caldera, delimiting the many valleys within it that may be explored today. While volcanic activity has been minimal since the Banco Bonito eruption, the caldera is not considered to be extinct. It is known that a magma chamber exists about 4.5 miles below the surface (Goff 2009), hot springs and fumaroles may be seen on the western side of the preserve and down to the community of Jemez Springs, and tiny earthquakes are measured on a regular