COUGAR, Wash. — In the dark, foggy shroud of an early fall morning, headlamps cast eerie lights on the faces of a dozen or so hikers lingering at a trail head that leads to the summit of the most active volcano in the continental U.S.

The shadowy silhouettes of Douglas and Pacific silver firs border the circular trail head, known as Climbers' Bivouac. Towering overhead, somewhere in the darkness, lurks the angelically named peak that in 1980 unleashed America's worst volcanic disaster.

The glowing headlamps converge on a powerfully built forest ranger who will help guide the party to the 8,365-foot summit of Mount St. Helens.

The dark obscures the hikers' faces, but from the assorted accents and conversations, I know I've joined a diverse group — men and women, retirees and high school students from British Columbia as well as New Hampshire — each sharing a common fascination with this infamous stratovolcano. I see gray beards, a couple of forest-ranger uniforms and the white baseball cap of the youngest member of our party, a fidgeting kid who looks eager to get on with the climb.

The voices grow silent as the lead climbing ranger issues a warning. This will be an eight-hour roundtrip hike along rough terrain, with an elevation gain of about 4,600 feet, he says.

"The biggest thing is: Don't jump off the rocks. Step off of them," he says. Injuries are not uncommon. Hiking Mount St. Helens is not for wimps. But the beauty of this unusual landscape is worth it.

FAMED PEAK STILL CASTS A HUGE SHADOW OVER REGION

From the seat of a passing airliner 25,000 feet overhead, Mount St. Helens resembles a lanced boil — a dirt-gray crater protruding from forest-green hills to the south and a valley of boulders, rivers and mountain lakes to the north. The volcano lines up along the Cascades, a magnificent mountain range featuring the scattered peaks of Hood, Rainier and Adams.

This landscape was forever altered on a blue-sky spring day in 1980 when the mountain erupted after weeks of temblors and steam blasts. More than 700 miles away in Northern California, I watched in amazement the next day as bits of ash floated onto my father's pickup truck.

As I plucked the ashy specks, I felt a connection with the volcano victims. Like them, I was at the mercy of the Ring of Fire, a horseshoe-shaped band of volcanoes and shifting tectonic plates that border the Pacific Ocean. Call it Mother Nature's mean streak.

Dew-wet earth and layers of pine needles on the forest trail muffle the sound of our boots as we march toward the summit of that same volcano that rained down ash and destruction 28 years ago. In addition to the rangers, this climb is guided by experts from the U.S. Geological Survey, who will explain the science behind the volcano's prickly temperament.

Researchers have been watching the volcano since it came to life again in 2004, venting steam, pushing out a slow-growing lava dome and setting nerves on edge throughout the Pacific Northwest.

For two years, the summit was off-limits to hikers until geologists declared the danger of imminent eruption had passed. In 2006, the Forest Service reopened the mountain, setting a 100-permits-per-day limit. But the permits routinely sell out. The volcano was awake, and everyone wanted a closer look — including me.

On the previous afternoon, during my hourlong drive from Portland (Ore.) International Airport to the nearby town of Cougar, my view of the volcano was blocked by dark green forests and lush foothills. Now, stomping up to the summit, I can't wait for the darkness to lift and the fog to part so I can see the peak that was once as symmetrical as Japan's Mount Fuji but is now as craggy as a rotten cavity.

As the morning sun peeks through the trees, I'm reassured that the mountain won't lash out soon. One of our leaders, Larry Mastin, a bearded, scholarly looking volcano expert for the U.S. Geological Survey, says we are safe — at least from the volcano.

We reach the timberline at 7:30 a.m. Now the hard work begins. Up ahead, we must navigate nearly three miles of jagged lava rocks, most the size of Mini Coopers.

Along the way, I strike up a conversation with geologist Carolyn Driedger, Mastin's wife. Her specialty is glaciers. I tease her, saying the marriage of two geologists has been 4.5 billion years in the making.

As we scramble over boulders, Driedger tells me how she narrowly escaped Mount St. Helens' 1980 eruption. She was working with David Johnston, a bright, 30-year-old geologist who was taking volcano measurements at an observation post six miles away.

Johnston had accurately predicted that Mount St. Helens would erupt laterally, not vertically. He also predicted the volcano would erupt sooner rather than later. He urged Driedger and a colleague to evacuate to a safe distance. No sense putting three people in danger, he said.

Driedger and the other geologist left the observation post. The next morning, Johnston radioed in his last words to the Forest Service headquarters in Washington before the eruption consumed him: "Vancouver! Vancouver! This is it."

The destruction unfolded like falling dominoes.

A 5.1-magnitude quake rattled the mountain, triggering the collapse of more than 1,300 feet of the summit. The collapse unleashed trapped gas in an explosion that could be heard as far away as Seattle.

The blast killed wildlife and toppled trees in an area of more than 200 square miles. Mud, rocks and melted snow raced down the valley of the North Fork Toutle River, finally stopping more than 13 miles away. Columns of smoke and ash shot up 12 miles into the sky.

Johnston's body was never found. Seventeen years later, a new observatory was named in his honor.

Back on the mountain, we scamper above a cloud layer, the peaks of the other Cascade Range volcanoes poking through the white fluff. Snowcapped Mount Adams protrudes in the east, and Mount Hood sticks out in the south.

"Amazing, absolutely amazing," a fellow hiker says as we sit on the jagged rocks, catching our breath.

Driedger looks down and points out a swirling cloud front approaching from the south. We don't have time to linger.

The first climber of our party clears the boulder field at about 11 a.m. Now we start up a steep gravel path to the crater's edge about a quarter of a mile ahead. Up here, the air is bitter cold and the wind whips fine rocks and sand in my face.

"Oh, yeah!" The shout comes from the first hiker of our group to reach the top.

A brutal wind blasts my face as I peek into the crater. The mile-wide cavity drops down about 1,300 feet to a beige, rocky dome, pushing up Earth's innards like a wound. Puffy white columns of steam vent into the brisk air.

On the other side, where the volcano expelled nearly a cubic mile of rock, lava and ash, the land is flat, dark and dead. In the distance, a young forest grows out of the ashen land.

At the crater's edge, Mastin, our volcanologist guide, explains that the volcano dome is growing by about a quarter of a cubic meter per second — or about 700 dump trucks of rock and soil daily. The viscous material squeezes out like toothpaste from a tube, then spills out in all directions.

As he speaks, a chunk of the crater's ledge a few yards away gives way, sending tumbling rocks into the crater. Minutes later, another part of the shelf crumbles. The sound of falling rocks startles me and several other hikers.

All eyes turn to look at the lava dome, but it remains motionless. Mastin is calm. The erosion is normal, he says. Nothing to worry about.

But we all know that volcanoes don't operate on a schedule. Like earthquakes, they are capricious and violent. I've seen enough. Veni, vidi, vici. Let's go.

I turn to give the lava dome one last look when I hear a commotion behind me. The other hikers have converged on the youngest hiker, who has collapsed near the summit. The teenager is in the fetal position, complaining of leg cramps.

It must be hypothermia, we conclude, because he practically ran to the top and was probably dripping sweat when he reached the frigid peak. We try to help him, offering water, an extra jacket and snow pants.

Over a forest ranger's radio, we hear a Forest Service supervisor say they won't send a rescue chopper unless it's a life-or-death situation. The kid's father looks on, worried.

The storm clouds that had pursued us are now roiling about 100 feet below. If we don't move soon, we will be overtaken by darkness or storm clouds or both.

As a group, we lift the kid to his feet and help him walk, one person under each arm. I grab his backpack and throw it over my shoulders. After hiking about 100 feet, he collapses again. The rangers massage his legs, but the kid crumples a few yards away. At this rate, I think, we won't get him over the boulder field before nightfall.

But our luck turns. The menacing storm clouds that pursued us open a view of the lush green hills of the Gifford Pinchot National Forest, the sparkling deep blue Yale Reservoir and Lake Merwin. The exhausted kid regains some of his strength. He begins to walk under his own power. The group plods over the boulders and by 4:30 p.m. we reach the timberline and begin the shady path through the forest.

Later, in the dark at the trail head where we started about 12 hours earlier, we wish one another well and slip into our cars. Doors slam. Engines roar to life. Wheels roll over gravel, and the craggy volcano disappears in our rearview mirrors.