A River Runs Through It

Posted on January 31, 2023

Gary Hart Photography: Sapphire Cathedral, Vatnajökull GlacierIceland

Sapphire Cathedral, Vatnajökull Glacier Ice Cave, Iceland
Sony a7R V
Sony 12-24 GM
.8 seconds
F/18
ISO 50

Among the greatest joys of my photographer’s life is the opportunity to witness rare and exotic beauty I might otherwise have missed. An erupting volcano? Check. The dancing colors of the northern lights? Check. Shafting light in a Southwest slot canyon? Check. Southern Hemisphere night sky? Check. The view from the bottom of the Grand Canyon? Check.

In my California-born-and-raised world, glaciers certainly qualify as beauty both rare and exotic. Fortunately, this photography life takes me to New Zealand, where I get to walk on a glacier, and most recently, to Iceland, where I actually get to walk in a glacier. How cool is that? (Very, actually—no pun intended.)

Vatnajökull is the largest glacier in Iceland, and the second largest in Europe. As recently as the 19^th Century, Vatnajökull extended all the way to the Atlantic, but thanks to our warming planet, in most places it is now a few miles inland.

As alarming as that is, a consolation prize is the beauty Vatnajökull’s shrinking has produced. Glacier Lagoon is filled with Vatnajökull’s meltwater and decked out in large chunks of calved glacial ice; nearby Diamond Beach is bejeweled with the remnants of the lagoon’s ice; and Sapphire Ice Cave (and its predecessors) was formed in the wake of Vatnajökull’s retreat.

Ice caves are dynamic phenomena that can change noticeably from week-to-week, and over a span of many weeks or months will eventually become unrecognizable. They form when glacial runoff finds, or makes its own, path through glacial ice. Since flowing water is always warmer than the surrounding ice, these voids and channels continue expanding as more ice melts. When the runoff finds a different path, or diminishes in the freezing winter months, the spaces in the ice remain and an ice cave is born (or reborn).

Perhaps the most striking feature of an ice cave is its color. Contrary to popular opinion, this blueness is not reflected color from the sky, but from an inherent quality of the ice itself. Snow is opaque, but centuries of pressure from snow accumulating above compresses the older underlying snow, forcing out air and leaving only translucent ice crystals. As sunlight passes through these ice crystals, all but the shortest visible wavelengths are absorbed, allowing only the blue wavelengths to pass through to bless our fortunate eyes.

Each year Don Smith and I take an Iceland photo workshop group to visit the current incarnation of the Vatnajökull ice cave, and each year it’s completely different. So far it has been in more or less the same location for every visit, but this time, using a bridge across a small creek near the entrance as a reference point, I noticed it had retreated at least 100 yards in the last year. The glacier guides say that within a year or two this cave could be inaccessible or completely gone, requiring them to find another ice cave to blaze a tourist path to. (They’re only open to visitors in winter, one more reason winter is my favorite time to visit Iceland.)

With two Iceland workshops this year (still playing COVID catch-up), Don and I visited the Vatnajökull ice cave twice, 9 days apart. This version is dubbed Sapphire Ice Cave by the guides (earlier versions have been Crystal and Diamond), about 9 days apart. This created a great opportunity to compare, contrast, and witness firsthand the gradual changes that accumulate with time to completely end the cave, or transform it into something brand new.

Iceland’s ice caves can be extremely crowded, making photography difficult. In previous years we’ve started well before sunrise to be the first out there, but this year the morning weather didn’t look good, so we switched to late afternoon to be the last people to leave. To lighten my load for the one-mile walk, I pared my camera bag to nothing but my (brand new) Sony a7R V body, Sony 24 – 105 f/4 G lens, Sony 12 – 24 f/2.8 GM lens, and Really Right Stuff Ascend tripod.

Upon arriving with our second group, rather than start shooting immediately, I took a couple of minutes to survey my surroundings and get a handle on what had changed in the last 9 days. The most obvious difference was the river running through the cave. Recent rain, augmented by warmer temperatures, had created mini (and not-so-mini) springs and even a couple small waterfalls that poured in from intra-glacier reservoirs and streams. And then there were the seemingly ubiquitous and aggressive ceiling drips that (given my many layers) were surprisingly adept at targeting my neck and sliding down my spine. All this water united on the cave’s floor to form the shallow but swift river splitting the length of the main chamber before exiting through the main entrance. (This new river made instantly clear the puzzling presence of a makeshift metal bridge spanning nothing but dry rock and dirt on our first visit.)

Soon other differences came into focus: in addition to the flowing water, I noticed subtly altered curves, a few missing or blunted outcrops, and a handful of overhead portals that provided new views to the sky above. At one point during our visit a small rockslide sent several dozen softball-size rocks crashing about 10 feet from an elevated ice shelf, an instant reminder of an ice cave’s perpetual dynamics (and of why visitors are required to wear helmets at all times in the cave).

Our guide, provided by our Iceland guiding service to assist both workshop groups, was fellow Sony Ambassador Albert Dros (Albert is from the Netherlands; Ambassadors in the US are called Sony Artisans), whose energy is matched only by his creativity (check him out). Albert had most of the group occupied photographing Artie, our ice cave driver/guide (yes, there were 4 guides for 12 workshop participants in the ice cave portion of the workshop: Don, Albert, Artie, and me), whom he had drafted as a model to establish scale for everyone’s images.

With a few minutes to myself, I was both ready and able to begin taking actual pictures. I warmed up by attempting to reprise compositions remembered from the earlier visit. But once I became comfortable with the ice cave’s changes, I moved on to new compositions that emphasized those differences.

I started by concentrating on the waterfalls with my 24 – 105 lens, using long-exposure motion blur to help them stand out. But when I noticed that the view beyond the cave entrance was filled with a nice mix of clouds and sky, I saw an opportunity to highlight the ephemeral river (and to test the dynamic range of the a7R V). Time for my 12 – 24 lens.

Setting up shop on the bridge, I started composing versions of the scene you see here, first horizontal, then vertical. It took a few frames, but I eventually found the combination of position on the bridge, tripod height, and left/right framing (at 12mm) that allowed me to include the new natural skylights on the left (with enough distance from the edge), all of the cave’s entrance (and the sky beyond), plus the ideal balance of river and ceiling.

I wanted to smooth the water enough to eliminate distracting (in my opinion) texture freezing the motion would create. Lacking a neutral density filter for the 12 – 24 lens, I stopped down to f/18 and dropped to ISO 50, which allowed a nearly 1-second shutter speed—just slow enough.

The river was in shadow, but the water’s blueness really came out with the extra light my camera was able to capture. As with the ice cave’s color, the color of glacial water also is not simply reflected sky—or in this case, the ice’s blue. Rather, the water’s color is actually determined by the glacial silt it carries.

To understand this, now might be a good time to mention the counterintuitive truth that even receding glaciers move forward. Gravity carries a glacier downhill, but the glacier can still be retreating despite this downhill motion if it melts faster than it advances. As a glacier moves, embedded rock fragments at its base behave like sandpaper, grinding the rock over which it slides into finer and finer particles, the finest of which is called glacial flour. As the glacial meltwater carries all this scoured rock downhill, the heavier particles soon sink, while the finer glacial flour remains suspended in the runoff.

Most of the light striking water infused with glacial flour is absorbed by the fine suspended particles, but the green and blue wavelengths aren’t absorbed; instead they scatter back to our eyes and we are treated to blue, green, or turquoise water. The exact hue of flowing glacial meltwater is determined by the size of the suspended particles and the wavelengths (color) they scatter.

The product of these glacial machinations is the overwhelming blueness you see here.

BTW

I continue to be blown away by the dynamic range of the Sony sensors. As you may know, I never blend images, so the ability to capture with one click the entire range of tones in a scene like this is extremely important to me. On my LCD (jpeg) preview, the shadows in this image looked nearly black, while the highlights appeared hopelessly bright. But I trusted my histogram and the Sony raw file, and a couple of tugs of Lightroom’s Highlights and Shadows sliders validated that trust.