Friday, April 15, 2011

The Day I Lived Through a Volcanic Eruption!

On clear days in Portland, Mt. St. Helens is a truncated cone, snowy white in winter and spring and turning to a smoggy purplish brown in summer and fall. But looking at the mountain from the north, at Johnston Ridge Observatory, the volcano is alien and terrible, a chasm filled with steam and smoke rising from wreckage like a beast from Mordor. The spires of the crater rim overlook a breach that opens onto devastated fields, the scale of which distance magnifies rather than diminishes in power.

In October, 2004, Mt. St. Helens came to life again. A series of small eruptions and lava flows formed a dome inside the crater, surrounded by Crater Glacier, the northwest’s youngest. Although these eruptions were confined to the crater, they continued for several years, prompting authorities to limit access to the mountain. Two years later, the volcano was still actively erupting lava, the dome continued to grow, and occasional plumes of steam and ash rose above the crater rim.

October 21st, 2006 was a cool, clear day. Along with other students in Portland State University’s geology department, I was at the mountain, studying the debris flow along the Toutle River and witnessing the lingering destruction caused by the 1980 eruption. Our second-to-last stop was at Johnston Ridge Observatory, directly facing the crater and only five miles distant. From the paved trails at the observatory, we could see across a shattered landscape into the crater itself.

The land has something of a Shakespearean tragedy to it, suggesting “Bare ruined choirs where late the sweet birds sang.” Facing north and west, I looked over miles of barren hills where once a forest stood. Today there is nothing there but stones and stumps, and blasted trees lay against the ground in neat rows as in a cemetery. Deer and elk, bear and mountain lion once roamed these slopes, shaded by old-growth hemlock and fir. You used to be able to hear running water among the dappled forest sunlight. You used to be able to hear the haunting calls of spotted owls and listen to the insistent tapping of pileated woodpeckers. If you sat still long enough, you used to be able to catch the iridescent greens of hummingbirds and the yellow flash of tanagers.

Now the land’s silence on a clear sunny day is unfathomable and deep. It does not draw tears or catch your breath, because it exists in long moments of untethered wonder. Listen, it seems to say, to the songs that are gone.

I looked away to the south, to the source of this absence lording over it. There was Mt. St. Helens like a tyrannical father in repose, wreathed in smoke and silence, full of brooding violence and swift judgment.

Steam rose from the dome and filled the crater – although I was too far away to see it, the slow eruption continued, with fresh lava pushing the dome skyward, melting the glacier and surrounding the crater rim with a gauzy haze. The valley before the breach was filled with hundreds of vertical feet of debris blasted from the guts of the mountain, a graveyard plain of pumice and pulverized rock scoured by mudflows and clouds of super-heated gas, layered with ash and split by stinking fumaroles. It was almost entirely lifeless, with only a few pioneering trees and hardy tufts of grass covering the slopes above tortured gullies and young river channels.

It was a very different view that day in 1980 when vulcanologist David Johnston watched the entire north face of the mountain slide towards him, leaving him just enough time to radio “Vancouver! Vancouver! This is it!” before the lateral blast of the eruption swept a thousand feet up and over the ridge that now bears his name.

It’s hard not to feel this landscape in your throat.

Inside the observatory, after viewing a film about Johnston, the eruption, and the aftermath, the curtains in the theater rose to reveal windows with a direct view of the crater and the scoured landscape in front of it. It was a forceful moment, as my film-oriented academic understanding of the eruption was again replaced with a gut-level, instinctual comprehension of the scope of the event.

We left the observatory in mid-afternoon and drove to Coldwater Lake, spreading out to hike along the shore. Even here, on the far side of Johnston Ridge, the power of the mountain was evident. Barren brown ridges, still covered in matchstick-like trees blown down by the eruption, surrounded the deep blue waters. Along the shore, alder and other shrubs – still the first wave of succession – grew thick and low, obscuring the view of Mt. St. Helens above Johnston Ridge.

I was near the front of the group with Professor Scott Burns when, at 3:13 pm, shouts filtered up from the rear: “Professor Burns, come quick!”

Turning around, I expected to find out that someone had hurt themselves, or had seen something unusual. It was the latter. At a clearing near the lake’s outlet, the alder parted for a view of Mt. St. Helens, and from the volcano’s jagged rim a dirty white cloud expanded in the air like a time-lapse thunderhead gathering strength. The volcano was erupting.

A bus-load of geology students went into full geek mode. Professor Burns began an impromptu lecture as the ash-cloud gained height and spilled out of the crater. For the next ten or fifteen minutes, the plume – filled with gray ash and white steam – rose two thousand feet above the mountain and spread west in the wind. But the eruption was short-lived, and as the plume began to disperse, we wandered back towards the bus.

It’s hard to say what it was like to witness this. I found out later that a magnitude 3.5 earthquake shook the nascent dome, collapsed a spire of rock, and caused the small eruption. I never felt the quake, and I was never in danger; the eruption never truly left the crater and ejected only steam and ash. But it was exhilarating all the same – and yet, rather anticlimactic.

I’d previously seen ash clouds from minor eruptions all the way from Portland, but I’d never been so close. And while this eruption was hardly anticipated, it felt removed. I stood on the cool shore of a large lake, with a fresh breeze shaking the alder leaves, and watched what might as well have been a cloud for fifteen minutes. There was no explosion, no ash-fall, no tremor in the earth. It’s hard to feel endangered at such a distance, especially in a crowd of professors and college kids more excited to take photographs than to consider the rarity and meaning of what they were aiming their cameras at. To take a photograph is said to steal a soul; in times like this, I’d argue that it steals your own.

As a group, we’d grown up on the 1980 eruption. Even if we weren’t alive then, or weren’t living in the northwest, we’d still studied that event and had, just half an hour before, been at the edge of the precipice. That was fresh in our minds, but hidden somewhat behind ridges of stone and familiarity. My background knowledge somehow dulled the emotional impact of what I saw – it removed the mystery, the edge. I can’t speak for everyone, of course, and I’m not saying I wasn’t excited. All I can say is that my excitement was more of an academic sort, full of intellectual perambulations quite opposite the hysterical running a larger eruption would’ve produced.

In short, and in retrospect, I’ve been looking forward to writing this story because it’s almost more exciting to tell it than it was to be there – I saw Mt. St. Helens erupt! I lived through a volcanic eruption! Have you ever lived through a volcanic eruption? I was just a few miles away as the ash cloud rose higher and higher!

It wasn’t any of that. To portray it that way is to live through the photographs I took, and embellish the story at the expense of the experience. My experience at Johnston Ridge was more powerful than my experience of the eruption, which was strange and significant precisely because of its lack of significance. And yet…“It would’ve been a trip,” Professor Burns said, “to have that happen when we were up there at Johnston Ridge.”

Saturday, April 2, 2011

What Did I Just Crawl Through? Adventures in Mt. St. Helens’ Lava Tubes

I’m only about six feet in. It’s dark, extremely dark, and I’m on my hands and knees. My knees ache from the rough surface and my elbows knock against rock. In the darkness, something clamps around my foot, and I hear the voice of a young woman behind me: “Sorry,” she says, “I can’t see where I’m going.”

Ahead of me, I hear more voices, and the sudden strobe of a camera flash illuminates the narrow round walls of the tunnel and the dark silhouette of a man in front of me. We’re in a lava cast: a straight, cylindrical void formed when lava flowed over a forest and solidified, leaving behind the cast of a tree that burned away nearly two thousand years ago.

When I was a student at PSU, I signed up for every available geology department field trip I could. This particular trip, to Mt. St. Helen’s south side, took me underground through the tree casts of Trail of Two Forests, and in the eerie formations of Ape Caves.

A mountain known best for its deadly 1980 eruption, Mt. St. Helens is young, erupting repeatedly over thousands of years. About 1,900 years ago, the volcano’s only known eruption of fluid basalt poured down the south flank of the mountain and created a formation known as the Cave Basalts. This flow left two outstanding geologic features: the lava casts at Trail of Two Forests, and Ape Cave, a short drive closer to the mountain.

The Trail of Two Forests is a brief, beautiful boardwalk hike that loops over a layer of moss-covered basalt. The lava that solidified here had the viscosity of molasses, and as it surged through the ancient forest, the surface cooled into a ropey pahoehoe texture visible through breaks in the moss. The flow cooled quickly enough to leave behind tree casts: from the boardwalk, you can peer into round wells where trees once stood, and crawl through the horizontal shafts where lava swallowed fallen trees. The smooth sides of these casts are etched with the impressions of tree bark and the contact between cooling lava and the burning, charcoal tree.

Dark, confined spaces make me nervous, and the narrow confines of the tunnel, just big enough to crawl through on hands and knees, made me very nervous. But after going through once, emerging with scraped up elbows and bruised knees, I was ready to go again. I convinced two students to return to the tree cast after lunch and crawl through with me, this time with a camera. I’d lost my apprehension, and I felt exhilarated, ready to go on to Ape Caves.

Ape Cave is the longest lava tube in the continental United States. When lava cooled near the surface of the thick flow, it solidified into a crust, forming a subterranean tube that carried molten rock underground for miles. A boy scout troop first explored the cave in the 1950's, naming it after a local outdoor group called the St. Helens Apes. The hiking club took their name from a 1924 incident in nearby Ape Canyon, where a group of miners claimed to have been attacked by a family of Bigfoot. I didn't see any sign of sasquatch, but there were plenty of hominids present as a bus full of geology students pulled into the parking lot.

With a total length of over 13,000 feet, and with several sections requiring at least a gutsy willingness to scale difficult walls and rubble fields in the dark, we weren’t going to see the whole thing. Instead, we descended a wooden staircase through a skylight at the main entrance and followed the lower cave to its debris-blocked end. From the skylight – essentially just a hole in the cave’s collapsed ceiling – the lava tube descends gently into darkness lit only by flashlight and headlamp.

Ape Cave contains many features not found in caves formed from water erosion. There aren’t any stalactites or stalagmites, which require water and minerals to form. Instead, the walls and ceiling are smooth, and covered in an iridescent bacterium known as cave slime. The black and white zebra stripes are caused by water vapor condensing from the breath of people exploring the cool cave – Ape Cave remains a fairly constant 42 F year-round.

As the daylight filtering through the main entrance fades, strange patterns and formations loom from the headlamp darkness. The cave wall is collapsed in one section, revealing oxidized bedrock baked red by the heat of the lava behind the smooth, crust-like wall. The ceiling closes in and opens again, like walk-ways above the sandy floor. Known as the “railroads,” these protrusions were formed when the lava tube was half full, and the surface of the lava began to solidify over the flow. At points along the tube, the floor is covered in boulders that have fallen from the ceiling.

Called breakdown, the larger boulders sometimes wedge between the railroads extending from the walls. The most prominent, an oxidized boulder nicknamed the “meatball’ by cavers, is fused to the extended walls by the heat of the molten flow. The mostly sandy floor alternates with rocky rubble from minor wall and ceiling collapses, and smooth stone eroded by water running through the cave in the near past. Moisture in the cave drips from the ceiling, further eroding grooves in the stone floor.

Everywhere the walls are brown, gray, black, white, glistening and smooth and when the lights are turned off, always silent… In the darkness, cupolas open overhead and the dim blue LED light from my headlamp filters into nothingness.

Elsewhere in the tube, the ceiling drops lower and begins to resemble the hall of a gothic cathedral or monastery, with a pointed arch extending into a dimly lit cavern, a ceiling patterned with cracks and water-formed lines that appear intentionally designed. The dusty floor here has levees, small ridges running parallel to the wall, as though to keep a flow of water between the wall and the floor.

At the end of Ape Cave, the ceiling drops so low that to continue, I crawled on my belly like a lizard, with my arms and legs splayed out until I reached the final, tiny chamber. With just three people the chamber quickly became claustrophobic, and it began to fill up as a line of students, tourists, and hikers on the other side waited to crawl through and blocked the passage out. Shouting through the narrow tunnel, I stopped people from entering the tunnel long enough to crawled back out, where the darkness and air were far more expansive than the flashlight walls and heavy air at the end of Ape Cave. I walked slowly back to the entrance, and when I ascended the stairs and left the cave the sunlight was dazzling, and the sight and smell of the thick verdant forest made me feel as if I’d woken from a night of troubled dreams. I’d only been underground for an hour, but it felt like more, like the first day out after a prolonged illness.

Standing deep within Ape Caves, you gain a sense of how powerful the Earth is. It’s difficult to fathom the force and power of the molten lava that once flowed through the cave at a thousand degrees or more, but in the darkness it’s easy to let imagination and even fear run wild. And at Trail of Two Forests, the new forest overlying the ancient basalt flow that destroyed a forest and left casts of the trees that died there demonstrates the resiliency of natural forces and the interplay between creation and destruction.

As William Stafford said, “The answers are inside the mountains.”