Arches National Park

The Desert Ecosystem. Deserts form where global weather patterns and geographic land forms create a climate characterized by less than 10 inches of accumulated moisture annually, and where potential evapotranspiration exceeds precipitation. Arches National Park lies at a latitude north of the equator where dry air masses constantly descend toward the surface of the earth. The area is also in the interior of a large continent away from marine moisture and in the rain shadow of the Sierra Nevada Mountains to the west. All of these factors act to produce the arid environment of Arches.

Arches receives an average of 9 inches of precipitation a year, most of it from melting winter snows. The elevation of the park (4,000 to 5600 ft.) and the snow create what is called a cold or high desert. Low moisture in the air allows more sunlight to reach the ground, raising daytime temperatures, another distinguishing feature of a desert. The average maximum summer temperature at Arches is 100 F. As a result of these unusual conditions, the plants found here are a unique blend not found in other deserts of the world.

Desert plants must be able to deal with extreme variations in temperature and water availability, as well as intense sunlight. In this high desert environment, temperatures fluctuate greatly, both daily and annually. In summer, highs climb well over 100 degrees F, while winter temperatures often drop below zero. On a hot summer day the temperature may fall 30 to 50 degrees F as night approaches, because of the low humidity and lack of cloud cover. As the sun sets, rock and sand, which do not hold heat well, release almost 90% of their captured solar energy back to the sky. Without clouds to hold the heat in, the air rapidly cools.

Surface temperatures in direct sunlight are commonly 25 to 50 degrees F warmer than the air temperature six feet above. Temperatures in the shade may be cooler by 20 or more degrees. Winter snow and violent thunderstorms fall on thin, sandy soils that do not retain much moisture.

Arch National ParkAdaptations. Plants use a variety of techniques to survive desert extremes. Some plants, referred to as “drought escapers,” make use of ideal growing conditions found in the spring when temperatures are cooler and water more abundant. These annual plants have a short life cycle and include the spring wildflowers that occur in showy abundance early each year.

Perennials, plants that live longer than one year, must deal with desert extremes in other ways. “Drought resistors” are plants that have made adaptations to get them through lean times. Cacti store water within their bodies, blackbrush drop their tiny, leathery leaves in dry weather, and yucca have tap roots up to 30 feet long which are able to reach water deep underground. Many desert plants have lightly colored, highly reflective leaves.

“Drought evaders” have even more radical adaptations. Moss, a plant not commonly associated with deserts, thrives because it can survive long periods of drought. When water is unavailable, it literally dries up. When water is suddenly plentiful, the plant readily soaks it up and becomes moist and green almost immediately. Mosses are usually found growing in the shade of larger plants or in cryptobiotic soil crust.

Another interesting adaptation is that of the Utah juniper, one of the most common trees in the southwest. During a drought, the juniper will shut off water flow to one or more branches, killing them in order to preserve the rest of the tree.

Other desert plants may grow only in specialized habitats. Moisture dependent monkey flower, easter flower and ferns all can be found in well-shaded alcoves with dripping springs. Cottonwood, willows and cattail, which require lots of water, can be found on river banks.

Arch National ParkThe Living Soil. A unique desert plant community that you are sure to see during your travels in Arches is cryptobiotic soil. This crumbly, black soil crust is made up of fungi, lichen, algae, moss and bacteria all living together in a symbiotic relationship, one in which all the members benefit from their communal coexistence. Cryptobiotic crusts are very important to the desert community because they stabilize the soil, prevent erosion, retain water, and provide important nutrients such as nitrogen to plants. A plant seed that lands in cryptobiotic crust has a greater chance of survival than one that lands in loose, dry sand. Unfortunately, cryptbiotic crusts are very fragile. One misplaced footstep can quickly turn crust to dust, and recovery and regrowth may take decades.

Arches National Park lies atop an underground salt bed called the Paradox Formation, which is responsible for the arches, spires, balanced rocks, fins and eroded monoliths common throughout the park. Thousands of feet thick in places, the Paradox layer was deposited across the Colorado Plateau some 300 million years ago when a sea flowed into the region and eventually evaporated. Over millions of years, the salt bed was covered with the residue of floods and winds as the oceans returned and evaporated again and again. Much of this debris was compressed into rock. At one time this overlying layer of rock may have been more than a mile thick.

Salt under pressure is unstable, and the salt bed below Arches began to flow under the weight of the overlying sandstone. This movement caused the overlying rock to buckle and shift, thrusting some sections upward into domes, dropping others into surrounding cavities, and causing vertical cracks which would later contribute to the development of arches.

As the subsurface movement of salt shaped the surface, erosion stripped away the younger rock layers. Water seeped into cracks and joints, washing away loose debris and eroding the “cement” that held the sandstone together, leaving a series of freestanding fins. During colder periods, ice formed, its expansion putting pressure on the rock, breaking off bits and pieces, and sometimes creating openings. Many damaged fins collapsed. Others, with the right degree of hardness and balance, have survived as the world famous formations of Arches National Park.

Faults deep in the Earth also contributed to the instability on the surface. The result of one such 2,500-foot displacement is called the Moab Fault and is visible from the Arches Visitor Center. Salt Valley was also formed by such a displacement.

Except for isolated remnants, the major rock formations visible in the park today are the salmon-colored Entrada Sandstone, in which most of the arches form, and the tan-colored Navajo Sandstone.

A nice thing about Arches is that “easy” doesn’t mean, “boring”, at least as far as the beautiful scenery that surrounds the park. The Balanced Rock Loop is one of the easier hikes around the base of a fragile and highly improbable geological rarity. Park Avenue is a medium hike where the trail descends steeply into a spectacular canyon. A slightly longer hike to the Windows takes you to two massive sandstone portals you can climb through. A half-mile trail takes you to the rim of a steep canyon where you can glimpse one of the nation’s most photographed natural features.

• Long Hikes

Arch National Park Delicate Arch
• Starting Point: Wolfe Ranch parking area
• Length: 3 miles round trip
• Time: 2 to 3 hours
• Elevation change: 480 feet
Take at least 1 quart (1 liter) of water per person! There is no shade. Open slickrock with some exposure to heights. The first half-mile is a wide, well-defined trail. Upon reaching the slickrock, follow the rock cairns. The trail climbs gradually and levels out toward the top of this rock face. Just before you get to Delicate Arch, the trail goes along a rock ledge for about 200 yards.

Devils Garden Primitive Loop
• Starting Point: Devils Garden Trailhead parking area
• Length: 7.2 miles (11.5 km) round trip, including all spur trails to points of interest
• Time: 3 to 5 hours
Longest of the maintained trails in the park, the Devils Garden Trail leads to eight awe-inspiring arches. Expect narrow ledges with rocky surface hiking and scrambling on slickrock. Not recommended when rock is wet or snowy. Trail guide available at trailhead.

Fiery Furnace (Fee Area)
The Fiery Furnace is a labyrinth of narrow sandstone canyons and fins. Visitors who want to explore the Fiery Furnace must obtain a hiking permit at the visitor center (fee charged), or sign up for a ranger-guided hike.

Double O Arch
• Starting Point: Devils Garden Trailhead parking area
• Length: 4 miles (6.4 km) round trip
• Time: 2 to 3 hours
Beyond Landscape Arch, the trail becomes more challenging as it climbs over sandstone slabs; footing is rocky; there are narrow ledges with exposure to heights. Spur trails lead to Partition and Navajo Arches. Dark Angel is one-half mile (0.8 km) farther. Trail guide available at trailhead.
Medium Hikes

Park Avenue
• Starting Point: Park Avenue parking area
• Ending Point: Courthouse Towers parking area
• Length: 1 mile (1.6 km) one way
• Time: 30 to 60 minutes
• Elevation change: 320 feet (98 meters)
From Park Avenue parking area, the trail descends steeply into a spectacular canyon and continues down the wash to Courthouse Towers. If you have a shuttle driver, you can begin at one point and be picked up at the other. For round-trip hiking, retrace your steps along the trail rather than walk along the park road.

Tower Arch
• Starting Point: Klondike Bluffs parking area, via the Salt Valley road
• Length: 3.4 miles (5.6 km) round trip
• Time: 2 to 3 hours
The trail climbs a steep, but short, rock wall, cuts across a valley and then meanders through sandstone fins and sand dunes. An alternate, shorter trail (0.3 mile [0.4 km] one way), begins at the end of the four-wheel-drive road on the west side of Tower Arch. This unpaved road washes out quickly in rainstorms; inquire at the visitor center about road conditions before heading out.
Easy Hikes

Broken Arch
• Starting Point: Sand Dune Arch parking area or Devils Garden campground across from campsite #40
• Length: 1.2 miles (2 km) round trip; 2 miles (3.2 km) including the loop
• Time: 30 to 60 minutes
From the Sand Dune Arch parking area, the trail cuts across a large meadow to the arch and continues to the campground. Loop trail leads through fin canyons with sand dunes and slickrock.

Balanced Rock
• Starting Point: Balanced Rock parking area
• Length: 0.3 mile (0.5 km) round trip
• Time: 15 to 30 minutes
A loop trail around the base of a fragile, picturesque rock formation.

The Windows
• Starting Point: Windows parking area
• Length: 1 mile (1.6 km) round trip
• Time: 30 to 60 minutes
A gentle climb up a gravel loop trail leads to three massive arches (North and South Windows and Turret Arch). An alternate return, slightly longer, is by way of the primitive loop around the back of the two Windows. The primitive loop trail starts at the South Window viewpoint.

Double Arch
• Starting Point: Double Arch parking area
• Length: 0.5 mile (0.8 km) round trip
• Time: 15 to 30 minutes
A relatively flat, sandy trail leads to the base of two giant arch spans which are joined at one end.

Delicate Arch Viewpoint
• Starting Point: Delicate Arch Viewpoint parking area
• Length: 100 yards (91 meters) round trip
• Time: 10 to 15 minutes
In addition to the short accessible trail, another (moderately strenuous) hiking trail climbs one-half mile (0.8 km) toward Delicate Arch and ends at the rim of a steep canyon that separates the viewpoint from the arch. (This is not the popular trail to Delicate Arch, which starts at the Wolfe Ranch parking area.)

Sand Dune Arch
• Starting Point: Sand Dune Arch parking area
• Length: 0.4 mile (0.6 km) round trip
• Time: 15 to 30 minutes
Trail leads through deep sand to a secluded arch among sandstone fins.

Desert Nature Trail
• Starting Point: Arches Visitor Center
• Length: 0.2 mile (0.3 km) round trip
• Time: 15 to 30 minutes
Discover the adaptations of plants and animals in the desert on a self-guided nature walk. Trail guide available at the trailhead.

Skyline Arch
• Starting Point: Skyline Arch parking area
• Length: 0.4 mile (0.6 km) round trip
• Time: 10 to 20 minutes
A short hike on a flat, well-defined trail. On a cold November night in 1940, a large chunk fell out of the arch, instantly doubling the size of its opening.

Although there are arches and natural bridges found all over the world, these natural phenomena nowhere are found in such profusion as they are in Arches National Park, located in Grand County, Utah, north of the town of Moab. The Colorado River forms the southern boundary of the park, and the LaSal Mountains are visible from most viewpoints inside the park`s boundaries. The park is situated in the middle of the Colorado Plateau, a vast area of deep canyons and prominent mountain ranges that also includes Canyonlands National Park, Colorado National Monument, Natural Bridges National Monument, and Dinosaur National Monument. The Colorado Plateau is covered with layers of Jurassic-era sandstones; the type most prevalent within the Park is called Entrada Sandstone, a type that lends itself to the arch cutting that gives the park its name.

Arches National Park covers more than 73,000 acres, or about 114 square miles. There are more than 500 arches found inside the park’s boundaries, and the possibility exists that even more may be discovered. The concentration of arches within the park is the result of the angular topography, much exposed bare rock, and erosion on a major scale. In such an arid area – annual precipitation is about 8.5 inches per year – it is not surprising that the agent of most erosion is wind and frost.

Flora and fauna in the park and its immediate surrounding area are mainly desert adaptations, except in the canyon bottoms and along the Colorado River, where a riverine or riparian environment is found. Where the landscape is not just bare rock, sage and other low shrubs are common; pinyon and juniper trees are also present. Cottonwoods, willows, and tamarisk predominate in the wetter areas within the park. The largest mammals are bighorn sheep, deer, coyotes, and bobcats; other animals include porcupines, jackrabbits, cottontail rabbits, foxes, mice, and squirrels. Lizards and snakes that have adapted to an arid environment are common, as are birds, both local and migratory, including canyon wrens, ravens, eagles, hawks, and waterfowl along the river.

The first known inhabitants of the area that is now Arches National Park were the archaic groups found throughout the West between 3,000 and 8,000 years ago. (A Folsom projectile point, up to 11,000 years old, was found just west of the Park in 1959.) The first to leave a distinct trace were the Anasazi and Fremont peoples, similar cultures that inhabited the Colorado Plateau from about A.D. 200 to about AD 1300. Arches National Park is just outside the Fremont cultural area, so the most common vestiges of ancient society are Anasazi. Within the park are many superb examples of rock art left in hidden canyons by prehistoric artists; dwelling sites and associated artifacts are also found.

The Arches area was inhabited later by two different historic groups of Native Americans, the Ute and the Navajo. Utes lived and hunted throughout the park area, and were responsible for driving out the first white settlers in the area as late as the 1850s. Arches was on the northern fringe of the Navajo lands, and although they passed through the area there is no evidence that Navajos lived within the park area.

The Old Spanish Trail passed through the Spanish Valley, where Moab is now located, and crossed the Colorado River just outside the park boundaries, but it is unlikely that many Spaniards ever ventured into the park. Juan Maria de Rivera, a Spanish trader, passed nearby as early as 1765, and by the 1840s the trail was a well-used route from New Mexico to California. Mountain men were known to travel in the area, but the only one known to have entered the present-day park boundaries was the enigmatic Denis Julien, who left an inscription dated 1844 in the Devil’s Garden area of the park. The first Mormon explorers entered the Moab area in 1854, and returned to found the Elk Mountain mission the following year; however, they were quickly driven out of the area by the Utes.

The Mormons returned to help found the town of Moab in the early 1880s, but it wasn’t until John Wesley Wolfe, a Civil War veteran, settled on Salt Creek in 1898 that the park had its first white inhabitant. Wolfe and his family lived on their homestead near Delicate Arch until 1910. Other residents of Moab were quick to note the natural wonders of the area, and visits to the arches, canyons, and fins were a regular occurrence by the turn of the century. In 1922, a local miner and prospector named Alexander Ringhoffer visited the area and was so struck by its unique beauty that he contacted officials of the Denver and Rio Grande Railroad, which ran just north of the park, to see if they would be interested in developing the area as a tourist attraction.

Through a roundabout series of events, the National Park Service was informed of the potential of the area for inclusion in the National Park System and, as a result, Arches National Monument was created by President Herbert Hoover in 1929. In 1933 and 1934 the Arches National Monument Scientific Expedition conducted an in-depth reconnaissance of the new monument. The scientists studied the geology, wildlife, plant communities, archeology, and paleontology of the area. The expedition was led by Frank Beckwith, a local newspaper editor and amateur scientist, who was responsible for many of the names of the arches and other features in the park, such as Delicate Arch, Landscape Arch, and Tower Arch. A detailed map of the monument was made, and Beckwith prepared a final report as well as several articles for publication, all of which contributed to the growing popularity of Arches National Monument.

In 1938, like many other western national monuments, Arches was greatly expanded by President Franklin Roosevelt, from its original 4,500 acres to almost 34,000 acres. Despite increasing tourist interest in the area, the first paved road wasn’t built into Arches until 1958. Other changes occurred in the 1960s, adding and removing various sections, and it wasn’t until 1971 that President Richard Nixon signed the law that changed Arches to a national park and set its size at the present 73,233 acres.

Because of its protected status, Arches National Park was never scarred by the “cat trails” or prospects of the uranium boom of the 1950s, nor by any other mining activities. In 1955-56, a natural gas pipeline was built through the northern sections of the park, leaving a scar that is still visible. Today Moab has become a center of a growing recreation area, with thousands of visitors flocking to the spectacular red-rock cliffs and canyons for mountain biking, river running, cross-country skiing, and other outdoor activities. Arches National Park is one of the most popular destinations among the many national parks and monuments in Utah and nearby states, and thousands of tourists from all over the world visit it each year. The danger today is not from mineral or other types of development, but that Arches, like most other national parks, will be simply “loved to death.”