🪨 Arches: What You Will Find

Arches National Park, by the town of Moab in Utah, holds in three hundred square kilometres the greatest concentration of natural stone arches in the world. Over two thousand have been documented.

For a formation to count as an arch, its opening must be at least ninety centimetres across. That is the only criterion, and it is the reason the number can be counted at all.

Why Here in Particular

Three hundred million years ago there was a sea here which evaporated and left behind a layer of salt over a kilometre deep. Salt is plastic under pressure: it gradually bulged and shifted beneath the sandstone laid down on top of it.

The sandstone above it cracked into parallel vertical slabs, which are called fins. Water got into the cracks, froze in winter, widened them, and the weaker spots in the middle of the fins crumbled all the way through. What is left above the hole is an arch.

That is why the arches here stand in rows and why there are so many of them. It is one geological process, repeated two thousand times side by side.

Delicate Arch

A sixteen-metre arch standing alone at the rim of a stone bowl, with the La Sal mountains behind it. It is on the licence plates of the whole of Utah, so most visitors know it before they see it.

The path to it is three kilometres one way, the climb about 150 metres, and the last stretch runs along a narrow ledge cut into the wall. There is no shade at all. In July you either walk it early in the morning or you do not walk it.

You can stand under the arch, but there is a queue for it. The best light is an hour before sunset, which everybody who is there knows.

Landscape Arch and What Happened in 1991

Landscape Arch, with a span of eighty-eight metres, is one of the longest natural arches in the world. It is also frighteningly thin — its narrowest point is about a metre.

In 1991, in broad daylight and in front of witnesses, a slab twenty-two metres long fell off it. Nobody was hurt, a tourist filmed it, and the trail under the arch has been closed ever since.

Seventeen years later, in August 2008, the whole of Wall Arch collapsed at night, one of the largest in the park. In the morning there was a heap of rock.

This is the most important thing about the park and the least talked about: arches are not a permanent state, they are a phase. Every one of them will fall eventually, and meanwhile others are forming.

Balanced Rock and Other Places Worth Stopping

Balanced Rock is a boulder weighing around three and a half thousand tonnes perched on a narrow pedestal right by the road. A smaller twin called Chip Off the Old Block used to stand beside it; that one fell in the winter of 1975.

Double Arch is two arches growing out of one place. The opening scene of the third Indiana Jones film was shot beneath them, so they look familiar in photographs even to people who have never been to Utah.

Fiery Furnace is a maze of narrow canyons between the fins. You go in only with a ranger or with a permit, because it is possible, without exaggeration, to get lost there within sight of the car park.

The Ground You Must Not Walk On

The dark lumpy crust between the rocks is not dirt. It is a living film of cyanobacteria, lichens and mosses called cryptobiotic soil. It holds the sand in place, retains water and makes it possible for anything to grow here at all.

One footstep crushes it and it can take decades to come back. That is where the sentence you will hear here constantly comes from: stay on the trail. It is not about tidiness; it is that this crust is the only reason the desert around is not simply sand.

Getting In

Since 2022, from April to October, entry is by timed ticket: you reserve an hour-long window to drive in. It was brought in after the park repeatedly had to close the gate because there was nowhere to park inside. The timed entry does not apply every year, but it is worth checking.

And one more name. In 1956 and 1957 Edward Abbey served here as a seasonal ranger and lived in a trailer with no electricity. He wrote Desert Solitaire out of it, in which among other things he proposed that cars be thrown out of the national parks. The book is a classic, and Arches now restricts entry — only not in the way he wanted.