Voyage under a glacier
by Doug O’Harra
For all I knew, we were lost in the labyrinth. The cave pitched downward, disappearing into darkness beyond the range of our headlamps. Two passages forked upward, their ice roofs dripping. Low crawlways led to either side.
Spelunker Curvin Metzler, who was guiding us through the cave system that ranges under a glacier about 45 miles southeast of Anchorage, was momentarily stumped. In half a dozen trips into the caves of Byron Valley, he had never seen so many passages converge in one place.
“Maybe you can get lost in a glacier cave,” Metzler said at last.
I kneeled nearby, pointing my flashlight and headlamp first into one cranny and then another. I sure didn’t know where to go.
Photographer Bob Hallinen had remained in the tunnel behind us, unable to get his camera gear through the small passage that led to our present position. In five hours, through almost a mile of sub-surface passages, we had seen daylight only twice.
Metzler chose to continue his strategy of choosing whichever passage pointed uphill.
“I won’t even try to explore those other passages,” he said to me. “We don’t have time.”
Moving uphill in a crabwalk, he reached a spot with a view of the farthest passage.
I scrambled after him, kicking loose rocks that clattered like breaking plates on the slope below. A tunnel almost high enough in which to walk upright rose uphill. A constant stream of air flowed back down. The exit was near.
With Metzler in the lead, we climbed a perfectly arched tunnel that rose about 10 yards to a T-shaped intersection. The passage in either direction led toward light.
To the left, the darkness was cut by a sliver of stark white light. The outside world. To the right, the light appeared fainter and bluish, as if illuminated by a neon sign. We decided to investigate.
Stooping down the right-hand tunnel, we entered a four-foot-high chamber in which the ceiling glowed.
In one spot, the ice was so thin you could almost see through it. If someone were to walk overhead, they would almost surely fall into our laps. We turned off our headlamps and sat on the cold rocks.
It was bright enough to read by — a room inside a glacier illuminated with blue light filtering through the ceiling. “Hallinen’s got to see this,” I told Metzler.
I decided to backtrack and bring the photographer to the room. It should only take a few minutes to reach him by scrambling through the tunnels. After all, he was only 10 to 15 yards away. Metzler continued on, exploring the passage to the exit.
But as I headed down the passage, it no longer seemed round and vaulted. With my headlight aimed down at the rocky floor, the dirty ice walls curved around me. I stopped. Was this the right way? It had to be. But which crawlway had I emerged from? And where was Hallinen?
I dropped to my hands and knees and twisted my head to light up the crawlways. They all looked alike: jumbled rocks, dripping water, glistening white ice. For a moment, I was lost. Though I couldn’t recognize any features in the ice walls, I could place that feeling — the primal, wordless terror of being trapped underground, having lost your way on the inside. It’s the feeling of fairy tales and Edgar Allen Poe, the same feeling etched on the face of the man who starved to death in Tom Sawyer’s cave.
I sat on the damp rocks for a moment, forcing myself to breathe deeply. OK, I reasoned with myself, this is not a serious problem.
After all, there aren’t that many choices — the correct tunnel had to be one of three. And, as I told myself, I could always retrace my steps.
I dropped to my chest and squirmed into the lowest passage. Within feet, I glimpsed the glow of Hallinen’s light. Calling over the ever-present sound of gurgling water, I told him about the room. Then, from behind me, Metzler, appeared. We could reach the blue room from the outside, he said.
So, in quest of an interesting photograph, the three of us descended through the passages, retracing our journey. Later, we would reach the blue room from the outside of the glacier. All was well. But the feeling of that brief moment when I thought I was lost lingered, with the same sort of breathless elation that follows a ride on a rollercoaster or a missed collision in traffic.
It was as though I had entered unknown territory and returned. I was eager to go back.
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That trip into the ice caves of Byron Valley in 1989 inaugurated an annual expedition for me. Over the years since, I’ve returned most fall seasons, if only to stand outside the entrance of the caves — and conclude that it wasn’t safe to enter. Sometimes you shouldn’t even enter Byron Valley. Snowfall up high produces avalanche danger so great that freight trains can overlap the valley from each side.
But when we’re lucky, the trips result in an otherworldly journey through the passages that riddle a glacier’s base like wormholes.
On these trips, I’ve traversed a half mile in a pitch-black tunnel to emerge into day light, standing at the bottom of a crevasse 50 feet deep. I’ve squirmed up into the bowels of the glacier itself, laying on a blue ice shelf with a million tons of compressed crystal above my head.
Where the glacial cones lay on the mountainside — replenished each year by avalanches — we’ve climbed hundreds of yards up one shaft as large and vaulted as a train tunnel. We’ve crossed subterranean fields of ice boulders as large as automobiles. We had broken an ice shelf from the ceiling of a tunnel that snapped like a pistol shot. We had found eerie spears of contoured ice frozen in the darkness — as well as other water-based speleothems — stalactites, drapperies, crystals. The beauty within a glacier is startling.
In Alaska, such caves occur beneath almost every glacier or avalanche cone, the mountain-sized piles of ice at the base of some avalanche chutes. Yet they may be the least explored natural wonder in the world.
“There’s probably only a handful of people in the world who have been in more than one,” said Harvey Bowers, a Wasilla resident and former editor of the Alaskan Caver, the newsletter of the Glacier Grotto chapter of the National Speleological Society.
Glacier caves form for two reasons. As a glacier moves, the ice can be blocked by a knob of rock, causing a channel to form on the leeward side of the blockage. These “obstruction caves” are thought to be rare.
Far more often, glacier caves form when melting water carves a passage through the ice. Warm air then flows into the passage and eats away at the walls. The process is called ablation. Essentially the same process creates limestone caves. But in a glacier, cave formation occurs a thousand times faster than in limestone. If limestone caves live and die over millennia, then glacier caves might rise, expand and collapse in a few seasons.
To a spelunker, the prospect of studying the same cave through all its phases is irresistible.
“You see the same thing in a glacier in two to three years as you would in a limestone cave in 5,000 to 10,000 years,” Bowers said.
Glacier caves house the same variety of formations found in limestone caves, Metzler added.
“But you can see them grow and change. In a limestone cave, that would take thousands of years.”
Glacier caves have probably been explored for as long as people passed by the streams emerging from glaciers and studied the yawning caverns beyond. The Tlingit Indians have a legend that in ancient times, people annually migrated through an ice tunnel near the Stikine River.
But the first published account of glacier caves occurred in 1860, when a scientist described two in the European Alps. Shortly afterward, explorers found a large tunnel in the Malaspina Glacier near Yakutat.
Though caves at Byron Glacier were first mapped 20 years ago by members of the local speleological club, they weren’t systematically explored until Bowers came to Alaska in 1971 to study geology at what is now Alaska Pacific University.
On one of his first weekends in town, some friends took him climbing at Byron Glacier. At the front of the middle snowfield, Bowers saw something he never expected to see: a cave in the ice.
He had grown up on a farm in the heart of West Virginia’s caving country. He’d been caving most of his life, exploring the hillside above his family’s farm including caves where saltpeter had been mined during the Civil War. When he entered college, he joined the National Speleological Society and began helping with exploration and expeditions.
In the caving world, Alaska was a blank place on the map. Later extensive limestone caves would be discovered in Southeast Alaska, particularly on Prince of Wales Island. But at the time, Bowers had never heard of any caves in Alaska. Yet here was a gaping hole, leading into darkness. It goes.
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Within a few weeks, Bowers returned to the Byron Valley, leading an trip of three or four people into the cavern.
“It was very exciting,” he said later. “You felt like you were on the edge of exploration.”
They crawled into a damp tunnel along a streambed that stretched for nearly 50 feet, then ended. The cave was in its final stages of collapse.
The group then found a second entrance, at the top of the snowfield. This time Bowers had better luck. A low, broad chamber followed the stream for 200 yards, deep into the snowfield. Though 30 to 35 feet wide, thousands of tons of compacted snow and ice above had pressed the ceiling to within 4 feet of the ground.
Bowers and the others noticed the first ice speleothems — pale draperies of translucent ice, stalactites and stalagmites. In the creek were tiny insects — what Bowers and the others called “snow fleas.”
Then, about 6 feet above the stream, an arched chamber opened up and stretched another 150 feet into the snowfield. Then it was over. The cavern was pressed to nothing.
“In a way, it was a disappointment,” Bowers said. “It was interesting that I was in ice, but I was used to fairly large caves. Here you could only go a half-mile.”
But Bowers kept returning until avalanches closed the valley, as they do every winter. Over the course of his trips, he mapped the cave — which was later published in the journal of the National Speleological Society. He found several other caves, including a 200-foot-long chamber underneath the upper glacier itself.
The following year, the cave collapsed in a concentric sinkhole that was rimmed with 40-foot-deep crevasses. Judging from the size of the collapse, the original chamber must have been mammoth — larger than a high school gymnasium. The resulting crevasses were treacherous, and one skier even fell into one, prompting an organized rescue.
Over the next few years, Bowers continued to explore the caverns at Byron Glacier. He became friends with Julius Rockwell Jr., a professor at Alaska Pacific University who served as president of the Alaska chapter of the National Speleological Society. Bowers, Rockwell and other also found a shaft and tunnel in the Eklutna Glacier, in Chugach State Park, in which the ice could be heard to move, slowing grinding its way downhill. Caves were also discovered and mapped in a dozen other glaciers in Southcentral Alaska.
With the publicity and the access, the caves at Byron Glacier were among the best-known in the world, perhaps second only to the Paradise Ice Caves on Mount Rainier. An expedition from Spain spent time in the caves. Two years in a row, Japanese university students spent several weeks mapping and exploring the area.
But glacier caves are constantly changing. Some years entrances appear, some years they don’t. Without much notice a cave might completely collapse to the ground. In the early 1980s, the Byron cave system did just that — and thereby fell from public attention.
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When the Byron caves reappeared in the early 1990s, only a small group of spelunkers in the Anchorage area paid attention. Cavers such as Metzler and Rockwell continue to visit Byron during the brief caving season in late fall — after freeze-up solidifies the ice, before avalanches close the caves and make the valley too dangerous to explore. Imagine climbing an icy mountain at midnight under an overcast sky. Exploring glacier caves requires similar skills — scrambling in the dark.
But there is a difference. On the mountain, a one-ton chunk of ice won’t fall from the sky. In a glacier cave, the roof can fall on you at any time.
“It isn’t quite like playing Russian roulette,” said Rockwell. “If you keep your wits about you, then you’re probably safer in that cave than you are in a car.”
Yet Rockwell’s assurance begins to sag some when the novice caver confronts a chamber littered with shattered boulders and girders of ice. Again and again, you’re reminded: The ceiling of a glacier cave can fall on you.
As a result, people should probe the underside of a glacier or snowfield only with an experienced caver who can recognize instability in the walls or ceiling. Vertical shafts and steep passages may require scrambling skills or ice-climbing equipment. If the air temperature rises above freezing, cave entrances can collapse without warning.
“It’s just amazing to me that there haven’t been a lot of people killed there,” said Bowers.
“Sometimes we could record a series of collapses from one week to the next.”
In the Byron Valley, persistent avalanches on the route toward the glaciers makes exploring the caves even more dangerous. Some of the ice fields lie at the base of an avalanche chute, and the upper valley is overlapped by avalanches every winter. Often, no safe route to the Byron caves exists. U.S. Forest Service intepreters at the Begich, Boggs Vistitor Center on Portage Lake have this advice: Don’t go in glacier caves at all.
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In mid-October of 1989, my first attempt to explore the Byron caves was a lesson in avoiding such dangers.
The rain fell in sheets and waves. The three of us — Metzler, Hallinen and myself — stood at the mouth of the middle ice field in Byron Valley. The creek boiled out of an opening large enough to drive a car through. A curtain of dripping rainwater guarded the entrance. Metzler motioned us forward.
“Get ready to run,” he said.
Ice boulders were scattered across the ground at the entrance. We picked through them and looked inside. The cave appeared capable of collapsing at a half-dozen spots.
We stepped back out to try another cave. Scrambling up-valley about a quarter mile, we reached the front edge of Byron Glacier itself.
There we found a cave opening as large as an airplane hangar, falling sharply to a creek bed about 30 feet below. From our vantage outside the cave, it was difficult to see how far it extended. Rocks and chunks of ice sprayed from the opening into the hole. Every few minutes, something large enough to smash a skull plummeted and cracked on the debris below. There was no safe approach.
We moved back to the middle ice field. Metzler led the way down a scree slope, sliding to some boulders.
“Watch out!” he called up suddenly. “There’s a cave here.”
Down under the boulders, a creek flowed into the entrance of a cave, yawning beneath a lip of hard, dirty ice. The three of us strapped on our headlamps and half-crawled into the cave.
It extended for 30 yards — then ended in a shelf of ice, where the ceiling had collapsed.
It was a new cave, one whose location had never been recorded before, Metzler said. Maybe it had just been carved or recently opened. At any rate, it didn’t go very far. And it was wet.
Still, Metzler was cheerful about it. Like Bowers, he grew up on a farm in cave country — Lancaster County in Pennsylvania. He had explored caves in West Virginia and Kentucky before moving to Alaska 12 years earlier. In caving, Metzler said, sometimes you find an endless maze of chambers with fascinating formations. And sometimes you find a tunnel with a blunt deadend.
The following week, we returned. The weather had turned cold with the area’s first snowfall. The creek had dropped. This time we could cross to the left-hand ice field, where Metzler had found caves before. Arriving there, we found the promising signs of a cave system.
Two entrances, each 10 feet high, opened into a large chamber. We approached the threshold and stopped, transfixed, at the portals holes that led into the bluish gloom. They looked like gigantic nostrils.
“It’s like a science fiction film,” Metzler said.
Walking inside, we found an ice chamber as large as a garage. It was dry. A steady stream of cold air flowed toward us out of a dark tunnel that veered to the right.
Metzler suited up — pulling on knee pads, hard hat and headlamp — then led us down the corridor. Just beyond the light from the entrance, massive ice chunks lay jumbled over the rocks where the ceiling had collapsed. Later, we would discover that an alternative passage lay buried on the other side of the jumble. But we continued on.
We arrived at a fork. A level passage to the right led toward the faint light of another entrance. It was in this direction that we would later find the glowing room and the labyrinth of tiny passages. But the brunt of the flowing air came downhill through a 30-foot-wide passage that rose sharply to the left.
We began climbing. The tunnel would eventually rise about 600 vertical feet from the cave entrance, tracing its path along the dry streambed of scree and dirt. Along the way loose rock shifted underfoot. The icy walls, scalloped with large indentations, reflected strangely in the flickering lights of our headlamps. Sound seemed to change. A rock kicked loose clinked like breaking glass. A shout lasted longer, not quite an echo but elongated and extended.
Gradually, we began to see the top: at first a dim light with no more strength than a streetlight seen through fog from a block away. But the more we climbed, the brighter it became. The rocks became wet; a stream grew in volume and began to rush.
We tried to cross a field of ice boulders, but they were too slippery for footholds. We wiggled and squirmed our way over them until they began to shift. Several kicked loose and rolled, filling the cave with their rumble.
At Metzler’s direction, we backed off, crossing 20 yards to the other side of the tunnel, where we found gravel and slate. Climbing closer to the uphill entrance, we saw how huge the cave had become — seemingly as large and cavernous as a circus big top.
By now the top opening was clearly visible above us: two massive arches, each with a stream tumbling down the rocks into the cave. We climbed faster, often in the stream itself.
Finally we reached openings that were 30 feet high and 20 feet across. Daylight. We snapped off our headlamps.
By then, we’d been in the dark for three hours.
With Metzler in the lead, we scrambled across the frozen creek and emerged at the top of the snowfield.
Portage Lake lay slate-gray in the distance. Beyond the lake, the hanging glaciers above Bear Valley glowed orange with the late afternoon sun. The cold air was clear enough to see the glimmer of flowing water in Byron Creek, half a mile across the valley. I had my bearings now.
But at our feet, the ice field dove hundreds of feet in a long, concave slope to the valley floor below. Except for a few shallow fissures, nothing broke its smooth surface. It looked solid, but I knew it was riddled with passages — and the promise of the unknown.
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