Robert Smithson's Spiral Jetty
Robert Smithson's 'Spiral Jetty' is one of the most iconic works of the 1970s land art movement. (Photo: Eric Broder Van Dyke /Shutterstock)

With its curlicue trail of salt-encrusted basalt rocks extending out into the rosy, microbe-rich waters of Utah's Great Salt Lake, Robert Smithson's land art masterpiece "Spiral Jetty" holds an esteemed spot on many an art lover's bucket list. However, even if you go out of your way to visit it on the lake's northern shore, there's no guarantee you'll actually be able to spot this rocky swirl. That's because the visibility of this famous earthwork is contingent on the lake's water levels.

When "Spiral Jetty" was first created in 1970, Utah's famous lake was experiencing a drought that caused exceptionally low water levels. Once the water levels returned to more average levels, the jetty became covered with water.

Aerial view of Robert Smithson's Spiral Jetty
Aerial view of Robert Smithson's 'Spiral Jetty.' (Photo: Erica/Flickr)

You might wonder why the artist didn't consider that his massive piece of art would be obscured for extended periods of time, but believe it or not, that was his plan all along. Well, sort of.

As New York Times Magazine explains, "Smithson anticipated that the lake would rise and fall, the residue of salt crystals causing the black rocks to glisten white whenever the water level dropped. But he miscalculated. Spiral Jetty was visible for about two years, then became submerged and stayed that way except for a few brief reappearances."

Because of that minor miscalculation, the only time you can see "Spiral Jetty" peeking above the water is when the levels are below 4,195 feet. This is likely to happen during a drought (like the one that occurred during the initial building of the Jetty), but in recent years, water levels have been dipping below the historic average (4,200 feet) more often than usual, likely as a result of what many scientists speculate are man-made influences.

The rosy, microbial waters surrounding the Spiral Jetty.
The rosy, microbial waters surrounding 'Spiral Jetty.' (Photo: Eric Broder Van Dyke/Shutterstock)

Bonnie K. Baxter, the director for the Great Salt Lake Institute, tells ScienceFriday that in addition to regional droughts, "water diversion along [the lake's] tributaries is partly responsible" for the unusually low levels. As it stands now, the levels sit at about 4,192 feet, and the jetty is often used by locals to gauge and estimate those levels.

Scientists are able to use this earthen spiral as a visual indicator to track the ecological changes occurring in the lake, and that really gets at the heart of what the entire land art movement is built upon — creating artwork that is inextricably dependent on the natural landscape that surrounds and comprises it.

Continue below to see more photos of this remarkable piece of land art, or better yet, take a trip out to Utah to see it for yourself!

Robert Smithson's Spiral Jetty
Robert Smithson's Spiral Jetty
Rosy-colored microbial water surrounding Robert Smithson's Spiral Jetty.
Rosy-colored microbial water surrounding Robert Smithson's Spiral Jetty. (Photo: Donald Fodness/Flickr)
Robert Smithson's Spiral Jetty
Robert Smithson's Spiral Jetty (Photo: joevare/Flickr)

Catie Leary ( @catieleary ) writes about science, travel, animals and the arts.