Exploring Rainier's summit steam caves

On top of Mount Rainier, under 150 feet of snow, Francois Le Guern prepared to launch a boat.

The craft was unimpressive: a 5-foot inflatable that barely contained the Frenchman's compact frame.

The setting was otherworldly: A frozen blue grotto the size of a grade school gymnasium.

Part of a labyrinth of caves that underlies the summit snowcap like the tunnels of a giant rodent, the grotto contains one of the planet's highest lakes. Meltwater dripping from the glistening ice walls and scalloped ceiling collects in the cavern bottom, creating a crescent pool up to 20 feet deep.

Le Guern, a renowned vulcanologist, cast off onto the frigid water, propelling his tiny vessel with plastic paddles. He dangled a thermometer like a fishing line and scooped up samples for chemical analysis.

"Yah-hooo!" he yelled, in a French-accented cowboy twang. "What a day!"

His colleague, Emmanuel Ponzevera, stood at the edge of the water, laughing and shaking his head. "Crazy Fan-Fan," he said.

Fan-Fan is Le Guern's nickname. It is the diminutive French mothers use for children named "Francois," and it seems apt for the 57-year-old scientist who tackles his work with boyish zest.

What Jacques Cousteau was to oceans, Le Guern is to volcanoes.

From Antarctica to Togo, Iraq and Cameroon, Le Guern has explored, studied and filmed more than 100 of the world's volcanoes. He got so close to the action during an eruption in the West Indies that his back was fractured by flying rock. On the flanks of Italy's Mount Etna, he set off explosives to divert a lava flow headed for a town.

He works with villagers and government officials around the globe to reduce the destruction wrought by volcanic outbursts, and his videos, models and educational programs are staples in French classrooms.

Attracted by the United States' most dangerous volcano, Le Guern has mounted two expeditions to Mount Rainier and hopes to return again this year. He spends much of his time in the ice caves because they provide one of the most direct links to the mountain's fiery interior.

Nearly 5,000 people trudge across Rainier's broad top every year, but few realize what is under their feet. Early climbers often sought shelter in the caverns, recording in their journals the misery of being alternately blasted by cold air and scalded by steam from hissing fumaroles.

It is these fumaroles, or steam vents, that create the world's most extensive network of ice caves. The hot gases rise from deep within the volcano, escaping through cracks and crevices in Rainier's bowl-like crater. The heat has melted out nearly two miles of caverns and worm-like passages beneath the plug of snow and ice that fills the crater like a scoop of ice cream in a giant cone.

Inside the caves, Le Guern can easily tap into the fumaroles, collecting the gases and analyzing them to find out what's going on inside the mountain. Right now, things are relatively quiet, with a stationary mass of magma sitting about six miles underground. When Rainier awakens and fresh magma starts to move in, one of the earliest clues will be changes in the gaseous emissions.

In the lake grotto - before his boat trip - Le Guern followed his nose to the fumaroles that carved out the chamber.

"I recognize that smell," he said, sniffing deeply. "See, it's sulfur."

He shined his headlamp on the muddy floor, where delicate yellow crystals bloomed around each of a half-dozen sputtering holes in the rock. (No sunlight reaches the caves, some of which are up to 400 feet below the surface.)

Le Guern knelt on the steeply sloping ground, poked a wire-like probe into the vents and read off the temperatures: 187 degrees Fahrenheit; 167 degrees; 176 degrees.

Ponzevera unloaded heavy vacuum tubes from his pack and hooked them to a small, plastic hose. He inserted the hose into the fumarole and sucked up a sample of gas, which would be analyzed at the Laboratoire des Sciences du Climat et de l' Environment, the research center near Paris where he works.

"We are making basic science," Le Guern said, dashing from one fumarole to the next.

But the work also has a direct bearing on one of the mountain's biggest hazards: The possibility that a large chunk of the volcano could break off and generate a mudslide big enough to bury nearby towns such as Orting and Greenwater. Mount Rainier is susceptible to collapse because the combination of heat, steam and corrosive gases is slowly "cooking" the stone, turning it into slippery clay.

"Look at this," Le Guern said, scooping up mud from the cave floor. He rubbed it between his fingers. "This used to be rock."

Learning more about the volcanic gases will help scientists better understand the transformation and how it undermines the mountain's stability.

The caves themselves also mutate over time.

In the early 1970s, the National Geographic Society sponsored one of the first expeditions to systematically explore and study the subterranean maze. Bill Lokey, a mountaineer and former chief of emergency management for Pierce County, was a leader of the effort, called Project Crater.

When he first tried to worm his way down one narrow passage dubbed the "rabbit hole," Lokey recalled, his companions tied ropes around his legs in case they had to haul him out feet-first. The group discovered chambers encrusted with crystalline hoarfrost so delicate it shattered under the slightest touch. An icicle as big around as an old-growth fir hung from the ceiling of another grotto.

"It was like going into Disneyland," said Lokey, who has returned to the caves several times and accompanied Le Guern on his recent Rainier trips. "Those caves are one of the most incredible natural phenomena in the United States, if not the world."

More than two decades later, the rabbit hole is much wider. The lake, which Lokey named Muriel, after his mother, has shrunk. The cave entrances - tucked in the moat between snow pack and crater rim - appear, disappear and migrate over the years.

"The hot spots on the volcano are different year to year, and the caves change accordingly," Lokey said. "It's a dynamic process."

The cave floors and walls bear the evidence of constant turnover. The scalloped ice domes are ringed in a bull's-eye pattern by layers of dirt that once dusted the mountain's snowy cap. Each summer, the snow melts down. Each winter dumps a fresh load. The result is a gradual downward migration of snow - and anything that's on it.

Objects left on the mountaintop years before now litter the floors of the ice caves: Scientific measuring sticks left behind in 1959, lost gloves, dead birds - even the wreckage of an airplane that crashed on the summit in 1991.

The caves have been little studied. Few scientists have the mountaineering skills to reach them, the lung power to camp on the summit for weeks at a time or the stamina to hump their research equipment up the 14,410-foot peak.

Le Guern and his team each carried up to 70 pounds of gear, from the inflatable boat to battery packs, lights and a video camera. The oldest member of the party, Le Guern shouldered one of the heaviest loads - including a whole ham. During past expeditions, he has carried smoked turkeys, bottles of wine and an accordion for evening entertainment. Lacking a musical instrument on his most recent Rainier ascent, he sang and yodeled during rest breaks. "You spend a lot of time together on these expeditions," he said. "You have to make it fun."

Passionate about his science, he also cheerfully admits that he selected his vocation as much for the adventure it affords and the chance to visit some of the world's most untamed places.

"I could have made a career as an alpine guide, but your muscles are getting older faster than your brain," he said. "This exercises my brain and my muscles, and keeps me in the mountains."

(Published 1999)