Why So Blue, Crater Lake?

Text by Jay Newman
(The text originally appeared in the book Uncle John’s Bathroom Reader: Nature Calls. I’ve posted it here as a sample of my writing. Images by Jay and Sue Newman.)

Here’s the story of an enormous volcano that blew its top, leaving behind one of the most beautiful, otherworldly places on Earth: Crater Lake National Park—home of the planet’s bluest water.

Crater Lake Cliff Layers

The Inside-out Volcano

Rising roughly 12,000 feet above sea level, Mount Mazama wasn’t the highest of the Cascades volcanoes. Its peak fell slightly short of Mount Shasta (to the south in California) and Mount Ranier (to the north in Washington). But in terms of pure mountainous girth, Mazama was the undisputed heavyweight champion of the Pacific Northwest. For more than 400,000 years, the composite volcano grew layer by layer in spits and spurts over top of a giant subterranean magma chamber in what is today southern Oregon. Mild eruptions, lava flows, gassy vents, and glaciation created a rugged landscape marked by frequent change.

The biggest change occurred just 7,700 years ago (a mere blip on the geologic time scale). Mount Mazama erupted in spectacular fashion. Ten cubic miles of ash and lava shot 30 miles into the sky. Pyroclastic flows laid waste to entire forests. One lava flow carved out 40 miles of what later became the Rogue River. Ash covered the ground as far away as Nebraska. The eruption ranks as a VEI 7, or “super-colossal,” on the USGS’s Volcanic Explosivity Index. (The scale only goes up to 8.) Put into perspective, Mazama’s eruption was 42 times stronger than Mount St. Helens’ blowup in 1980. Geologists believe it to be the most violent Cascades eruption of the past million years.

Because Mazama was so wide, after all the lava emptied from the chamber, there was nothing left to hold up the mountain. Result: Several million tons of earth, rock, and ash collapsed into the chamber. When the dust cleared, what had been a mountain was now a mountain-sized hole. The volcanic caldera formed a nearly perfect circle six miles wide and 4,000 feet deep. Over the next few centuries, the volcanic activity slowly subsided while the caldera steadily filled up with snow and rain. And Crater Lake was born.

Crater Lake Cloud Shadows

Cloud Shadows

The eruption occurred recently enough that there were witnesses. The Klamath and Modoc Indians both lived nearby, and the mountain blast shook them to the core. The Klamaths’ name for Mazama was Moy-Yaina (“Big Mountain”). According to their creation myths, living deep inside the mountain was Llao, the spirit chief of the underworld. One day, he emerged and saw a beautiful maiden named Loha wandering in the forest.

Llao fell in love with Loha, but she was the chief’s daughter, and rejected the hideous god. Angry, Llao sent fire and thunder from the mountain over nearby Klamath Lake. The people would have perished if not for Skell, the spirit chief of the sky. He fought on their behalf and defeated Llao. To ensure that he could never return, Skell covered Llao’s lair with earth and then filled the hole with water. The Indians renamed it Tum-sum-ne (“Mountain with the Top Cut Off”). And Crater Lake was born.

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Llao Rock

That story was passed down for thousands of years, and for the most part, the Indians stayed away from the lake (although there are stories of at least one brave explorer who ventured into the fuming caldera before it filled with water). The Indians, believing the lake to be sacred ground, also kept its existence a secret from white settlers. A group of gold prospectors finally discovered the lake by accident in 1853. Struck by its beauty, they spread the word to others. Before long, curious adventurers made the difficult journey through thick forests, across hardened lava fields, and up the steep terrain to see it for themselves.

One such adventurer was William Gladstone Steel, who had been hearing stories of the lake’s splendor ever since he was a teenager in the 1870s. Steel finally made it to the southwestern part of the rim (a spot called Discovery Point) in 1885. He was amazed: “All the ingenuity of nature seems to have been exerted to the fullest capacity to build one grand awe-inspiring temple the likes of which the world has never seen before.”

Rising from 1,000 to 2,000 feet above the shore, the rim of Crater Lake offers incredible views. The first sight that struck Steel (and most visitors) was the crystal-clear blue water. It was bluer than the sky. Across the lake, the vertical cliffs of the rim were also colorful, marked by towering castles of orange lava deposits, bright yellow lichen, white speckles of snow, and forests of evergreen trees. On a calm day the view is extra special: Glassy reflections create abstract patterns on the shore six miles away.

Crater Lake Moody Afternoon

Wizard Island from Discovery Point

Steel was also taken by Crater Lake’s other prominent feature, a conical island that rises more than 700 feet out of the southwestern portion of the lake. It’s also covered with volcanic rock and forests of pines, fir, and hemlock. Reminding Steel of a sorcerer’s cap, he named it Wizard Island. Over time, Steel named several more of Crater Lake’s features, including Llao Rock and Skell Head. And he was the one who called the ex-mountain Mazama, the name of a mountaineering club he belonged to.

Steel became Crater Lake’s biggest advocate. He brought in tourists, scientists, surveyors, and developers. In 1886 he hired Clarence Dutton of the United States Geological Survey to measure the lake’s depth. “As the visitor reaches the brink of the cliff,” wrote Dutton, “he suddenly sees below him an expanse of ultramarine blue of a richness and intensity which he has probably never seen before, and will not be likely to see again.” Steel and Dutton knew the lake was deep, but it wasn’t until they lowered a piano wire at various points along the surface that they grasped just how deep: nearly 2,000 feet.

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Hikers on the Rim

Steel was instrumental in convincing President Theodore Roosevelt to designate the area as the sixth U.S. national park in 1902. However, if Steel had gotten his way, there would have been a lot of development there: He wanted to build an elevator to take visitors from the top of the rim to the shore, and a bridge to Wizard Island. His colleagues at the National Park Service wanted to keep the area pristine, though, and Steel lasted only three years as Crater Lake’s superintendent before he was ousted.

Today, there is minimal evidence of man’s impact at the park. There’s a lodge and a gift shop on the south rim, and the 33-milelong Rim Drive blends into the landscape as it circles the lake. It offers dozens of amazing viewpoints in the summertime; most of the road is closed during the long winter. Even so, the national park is open year-round, and receives about 500,000 visitors annually.


Crater Lake wears its geologic past on its sleeves. You can actually look at the inside of a sleeping volcano. Here’s some of the science and superlatives of the “Gem of the Cascades.”

• That’s Deep. Modern sonar readings show that Dutton was pretty close to the mark. The lowest part of the lake bed is 1,949 feet beneath the surface. That ranks Crater Lake as the deepest lake in the U.S., and the ninth deepest on earth. If the Empire State Building were lowered into the lake (not counting for water displacement), by the time the ground floor reached the bottom, the top of the spire would be 500 feet below the surface.

Crater Lake National Park Sunset

Crater Lake in Winter

• A Perfect Balance. Most of the world’s lakes are fed by streams and rivers, and drain into streams and rivers. Crater Lake does neither. It is filled solely by precipitation. (Average rainfall per year: 66 inches. Average snowfall: 44 feet.) The lake loses its water through evaporation (and to a lesser extent, by seepage into the porous rock). These processes—precipitation and evaporation—balance each other out so well at Crater Lake that the surface rises and falls only by a few feet every century. (A single drop of water’s “residence time” in the lake is about 150 years.) Plus, because of Crater Lake’s great depth, the surface rarely freezes.

• I Can See Clearly Now. Crater Lake contains what may be the clearest, purest water known to exist. In most lakes that boast clear water, you can see about 16 feet below the surface in broad daylight. But in Crater Lake, it’s possible to see to depths of more than 100 feet. The deepest scientific measurement has been 142 feet, a world record. Several factors contribute to the lake’s clarity: Because no rivers run into it, no silt gets deposited. There’s little pollution because of Crater Lake’s remoteness (the nearest big cities—Portland, San Francisco, and Reno—are each hundreds of miles away). There are also very few organic materials or dissolved minerals in the water, and the human impact around and on the lake is minimal.

• The Blues. How can the water be so clear—and so blue—at the same time? Actually, it’s so blue because it’s so clear…and so deep. Here’s how it works: As sunlight penetrates the lake, it absorbs all the colors of visible light except for blue, which it reflects back. The deeper and clearer the water, the more blue gets reflected.

• New Growth. Wizard Island is one of two new volcanoes that have risen out of Mazama’s caldera (the other is still underwater). At barely 6,000 years old, the island is very young, yet many of the trees that grow on it are very old, some more than 800 years. There’s a trail that winds through forests and large lava rocks to the top of Wizard Island’s cone, which contains its own small caldera.

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Phantom Ship

• Phantom Ship. Mazama’s demise unearthed some very old rock formations, including Crater Lake’s other island, Phantom Ship. This spire of 400,000-year-old andesite lava was left behind by an ancient eruption. When viewed from the rim, the island looks like an old sailing ship, hence the name. The rocky spires rise 163 feet above the surface; the island itself is about 300 feet long. Clinging to the rocks are an astounding seven species of trees.

• The Old Man of the Lake. More than a century ago, a large hemlock tree fell from somewhere on the rim and landed in the lake. Since then, the 30-foot-long tree has been traveling along the surface, carried by the wind, with only a few feet of its exposed, bleached trunk bobbing above the water. It’s somewhat of a mystery as to why this tree—and no other—has become a floating island. Just another curiosity of Crater Lake.

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Clark’s Nutcracker

• Life Will Find a Way. Crater Lake might seem inhospitable—the rim is more than 7,000 feet above sea level, and most of the year it’s blanketed in snow. But like all volcanic regions, it has a thriving ecosystem. The most abundant life are the mangled, windswept trees. There are also several species of colorful wildflowers that enjoy their “spring” in September due to the area’s high elevation—among them Indian paintbrush, penstemon, lupine, monkey flower, and shooting star. Black bears, elk, mule deer, and bald eagles share the park with foxes, pikas, squirrels, snowshoe hares, several species of songbirds, and big, furry moths. Most surprisingly, there are rare black garter snakes that live on Wizard Island. They’ve adapted to blend in with the dark rocks.

• Into Llao’s Domain. There have been a few scientific expeditions—manned and unmanned—to see what lies at the bottom of Crater Lake. Scientists have learned that the area is still active— steam vents enter the water at great depths. That allows primitive life-forms to exist more than 1,000 feet below the surface, which actually receives faint bits of sunlight on clear days. But perhaps the biggest surprise came at depths of 100 to 460 feet along the lake walls—forests of moss several stories thick.

Fishing at Crater Lake

Fishing from Wizard Island

• Gone Fishin’. Can you fish in Crater Lake? Yes, but there is just one access point to the lake itself at the bottom of a steep, milelong trail from the rim down to Cleetwood Cove. Docked there are the only two boats allowed on the lake. Operated by the National Park Service, they take visitors to and from Wizard Island. The lake itself has no native fish, but William Gladstone Steel introduced some fish and shrimp in late 19th century. A few more stockings occurred over the next few decades, but the practice was stopped in 1941 to preserve the water’s natural purity. However, some kokanee salmon and rainbow trout still live in Crater Lake. Fishing from the rocky shore of Wizard Island offers anglers one of the most exotic places on earth to cast a line. (You can also swim in Crater Lake, but the water is quite cold, rarely topping 60 degrees in the summer.)

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Vidae Falls

• Beyond the Rim. There’s a lot more to the park than just the lake. One attraction is the Pumice Desert. This five-square-mile area lies just north of the rim. Small, light lava rocks—which cooled after Mazama erupted—form a layer several feet thick. Although it looks from a distance to be lifeless, there are 14 species of plants that thrive in this desert. Another incredible geological feature of Crater Lake is known as the Pinnacles—a steep river canyon full of hardened steam vents that stick up like spikes out of the sloping walls. And what would a Pacific Northwest park be without a waterfall? Vidae Falls cascades down the south side of the old mountain. Get there in late summer for the wildflower displays.

Will the volcano erupt again? Most likely. The constant change that shaped the region is stull in flux. What scientists don’t know is how much magma—if any—still remains in the chamber, and just how much pressure is building up. Future activity is likely to happen just east of the lake, where the geologic “hot spot” now lies. What’s more worrisome is the chance of a large earthquake causing landslides and huge waves on the surface. A really cataclysmic seismic event could rupture the rim wall and cause the lake to drain, creating a flood of 4.6 trillion gallons of water. But for now, Mazama remains at rest.


Jay and Sue Newman

Prints of Crater Lake available on our SmugMug page.

Crater Lake National Park’s official site.

More about the Bathroom Readers’ Institute here.


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