ALTAGRACIA, Nicaragua - On the road south from the international airport in Managua, Nicaragua swooshes by, unfurling in buzzing, humid green. Fields of swaying banana trees recede from the road in rows, the shaggy fronds bouncing against a searing blue sky.

I look south toward the twin conical peaks of Concepción and Maderas hovering over the horizon. It is Concepción that worries me. It is the active volcano I had committed to scaling.

Volcan Concepción towers 5,280 feet up from Lake Nicaragua, Central America's largest lake. (The lake is also known as Lake Cocibolca, the cha-cha-line name I prefer: Co-ci-bol-ca - hey!)

The volcano and its neighbor, Volcan Maderas (4,573 feet), make up the island of Ometepe, meaning "between two hills" in Nahuatl, the indigenous language.

Maderas is dormant, but Concepción sporadically unleashes ashy belches or, less commonly, lava flows. Although there hasn't been a major eruption in more than 50 years, Concepción fired off a column of ash in November 2007 that dispersed as far as Managua, 60 miles northwest, and prompted a series of small earthquakes on the island.

Ometepe isn't easy to get to. After you take an hourlong ferry ride, the island feels as isolated and primordial as it really is. When Nicaragua erupted in civil war in the 1980s, Ometepe maintained its distance, and there's an unruffled feel to the island not found elsewhere in the country.

I arrived in Altagracia late in the afternoon, checked into a leafy single bungalow at Hotel Central and met Alan, the Nicaraguan who would escort me and five other hikers on our 12-hour trip.

At 4 the next morning, I was carbo-loading on hot dog buns and guzzling black coffee, the best nourishment our hotel could offer at that hour. We convened in the lobby, decked out in our climbing finest - assorted ensembles of quick-dry, sweat-wicking layers and Gore-Tex. Alan arrived wearing ripped blue jeans, a white "Surf's Up" T-shirt and loafers.

We set off in dense, humid darkness along a knobby dirt road. As the trail gradually increased in slope and decreased in width, we walked under swaying banana trees and shiny coffee bushes, past homes with turkeys strutting through the yards. As hazy light began to slant through palm fronds, howler monkeys barked at us from the canopy high above.

Small villages popped up sporadically through the dense foliage that flourishes in the rich, volcanic soil. Many of the 38,000 residents of Ometepe make their livelihoods in this soil, harvesting plantains, rice, sugarcane, corn, coffee, and bananas.

As we climbed, our posture changed like a reverse time lapse of human development. At first, I charged straight ahead like the Homo erectus I'm descended from, but as the terrain got steeper, I slouched, closer and closer to the ground, until I was using my hands as much as my feet. Within an hour, the trail disappeared, and we simply tacked back and forth over the debris accumulated through a volcano's long life.

Although the view from the slope of Concepción is said to be spectacular, whoever said so had the good fortune to climb on one of the few days when its top half wasn't shrouded in clouds.

I recalled tales of hikers perishing before the Nicaraguan tourism board mandated guide accompaniment in 2006. How could someone get lost on a volcano? I had thought. You just go down. But as the mist enveloped me so completely that I couldn't hear or see any of my companions, I started to understand.

As we struggled up the exposed, steep face, the leafy guanacaste trees decreased until all that was left to hold onto was a squat, beefy plant with thick, spiny leaves two feet across.

When all traces of green disappeared, I tried to creep up the loose volcanic rock on my stomach, to keep my center of gravity as close to the volcano as possible. It was here - while gusts of wind pummeled my back - that I started to wonder about this volcano-climbing business.

Suddenly, the slope stopped, dissolved into sulfurous fog. I collapsed on the warm, gritty volcanic ash. A cold, hard wind at my back, the hot volcano beating beneath me, I crept toward the edge of the crater.

Here it was - my big moment. I was about to look into the bowels of hell.

Hell's bowels sure were white and foggy. No molten lava spitting out - only the lonely swirl of dense fog. This was more forlorn Mount Olympus than Satan's lair.

"Can you ever see lava?" I asked Alan.

He shook his head, then urged us to pack up and begin our five-hour descent. I learned later that the guides were reluctant to spend more than a few minutes at the crater lip for fear of eructos de ceniza - ash burps.

To the dismay of my 6-foot frame, our descent dropped us back another notch on the evolutionary scale, as we picked our way down on hands and butts in a perverse crab waddle.

By the time we reached stand-up human status, my quads were just about expired. Ten hours and 55 minutes after our departure, Hotel Central appeared on the horizon. We stumbled to our rooms, where very cold showers washed layers of Concepción down the drain.

And I checked "climb really tall active volcano" off my life list.

Climbing Volcanoes

American, Continental, and Copa Airlines fly to Managua from Philadelphia with one stop. The lowest recent round-trip fare was about $757.

It's a 11/2-hour drive from the airport to San Jorge to catch a ferry to Ometepe. Paxeos Shuttle will take you from Managua to San Jorge for $35 and accepts online reservations (www.paxeos.com).

In San Jorge, ferries leave about every hour for Moyogalpa and cost $1 to $2, depending on the size and speed of the boat. Buy a ticket on the dock.

Places to stay

Altagracia and Moyogalpa are good bases for hiking Concepción - both offer direct access to trails up the volcano. Unless you're splurging, don't expect a hot shower.

In Moyogalpa, Hotel Ometepetl (phone: 011 505 2 569 4276) offers air-conditioned doubles for $25 (a luxury on Ometepe) and a restaurant.

In Altagracia, Hotel Central (011 505 2 552 8770) is quiet and clean, with a full-service restaurant and helpful staff who will get up at 4 a.m. to make you coffee and see you off. Private rooms start at $7, but for $9 you can get a one-room cabin behind the main building.

The only ATM on Ometepe is in Moyogalpa, so be sure to have plenty of cash before venturing out. Most establishments accept cordobas or dollars ($1 equals about 21.25 cordobas), but many don't accept credit cards.

Tours

The Nicaraguan Tourism Board requires a licensed guide to accompany hikers on both the Concepción and Maderas volcanoes. Most hotels can arrange a guide. Depending on the size of your group, expect to pay $12-$14 a person, plus tip. Tour agencies can also set up lodging and guides in advance.

More information

www.visitnicaragua.com

- Megan KimbleEndText