Then and Now

Skyline Arch Rockfall
an arch with a large boulder on one side the same arch with the boulder gone. there is a larger opening
Skyline Arch before the 1940 rock fall NPS Photo
Skyline Arch after the 1940 rock fall NPS Photo

Arches usually form slowly, but quick and dramatic changes do occur. In 1940, a large boulder suddenly fell out of Skyline Arch, roughly doubling the size of the opening.

The arch now has a span of 71 feet (21.6 m) and a height of 33.5 feet (10.2 m).



Balanced Rock
A massive rock perched on a smaller pedestal. A smaller pinnacle stands to the right. A massive rock perched on a smaller pedestal. The smaller pinnacle to the right is gone.
NPS
NPS/Neal Herbert
Balanced Rock is made of two different rock formations. The rock itself is Entrada Sandstone, the primary arch-building formation in the park. The pedestal it sits on is part of the Carmel Formation, which erodes more easily.

Formations in the park are consantly changing. Note the small pillar to the right of Balanced Rock in the historic photo. That formation, dubbed "Chip Off The Old Block," fell in the winter of 1975-76.


Marching Men
a black and white photo of stone spires a dead juniper tree is in the foreground with two living junipers to the right. a color photo of stone spires. The dead juniper tree looks unchanged, and the living trees have grown very little.
NPS
NPS

On the Colorado Plateau, sparse rainfall and nutrient-poor soils facilitate slow rates of native plant growth and decay. Captured inadvertently by a scenic photo in the early 1920s, a dead juniper tree remains virtually unchanged nearly 100 years later. Nearby, two living junipers appear to have grown little. How long might a dead tree like this last where you live?



North Window
a black and white photo of North Window. A man stands under the arch on the right side. There are plants and soil on the stone below the arch. a modern photo of North Window. Several groups of people stand and sit beneath the arch. The soil and vegetation below the arch are gone. Slickrock is visible.
NPS
NPS
From 1944 to 2015, several million people from around the world have enjoyed North Window Arch. As we can see in this comparison, soil erosion is a serious concern as regional visitation increases. 

The desert may look rugged, but its ancient shrubs and biological soil crusts have few defenses against trampling from human feet or off-road vehicles. You can us protect the desert environment by staying on established roads and trails.


Arches Entrance
A black and white photo shows a sign reading "Arches National Monument" and a 1950s-era car sit in front of a tall rock wall in the background a vehicle drives on a paved road before a tall red rock wall
A 1950s-era photo of the entrance to Arches National Monument NPS
A 2010s-era photo of the entrance to Arches National Park NPS/Neal Herbert


Last updated: April 20, 2018

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PO Box 907
Moab, UT 84532

Phone:

(435) 719-2299

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