The Windows and Double Arch — Similar Shapes, Different Mechanics
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Transcript
The Windows area is useful because several arches can be compared at close range. Similar-looking openings can develop from different fracture patterns and erosion histories.
At Double Arch, erosion worked from above as well as from the sides. Water followed joints and potholes, enlarging weaknesses until two large openings developed beneath a shared mass of rock.
The Windows themselves formed where erosion penetrated fins along fractures. Once an opening exists, weathering continues to enlarge it.
The lesson is that an arch is a category, not a single recipe. The park defines a natural arch by an opening through rock, but each opening has its own structural history. The forms look architectural because gravity produces curves and spans that resemble engineering, yet no designer calculated the load.