Victor Hugo Calderon, 45, remembers when volcanic ash was so thick in the air that the sun disappeared at noon, so thick on the ground that cars became mired as if in snow.

"We had to walk around with handkerchiefs over our faces and hats on to keep the cinders out of our hair," Calderon said, recalling those days with a smile as if he could hardly believe it all had happen.

Like most Costa Ricans who lived near Irazu volcano during its two-year eruption in the early 1960s, Calderon has a sense or deja vu when he reads reports of the Mount St. Helens eruption in Washington State.

But while the blowup in the Pacific Northwest was a rarity for the United States, the people of Central America are all too familiar with volcanic disaster.

There are 34 active volcanoes in the region, and people here learned long ago how little is known about the forces at work beneath the earth, how devastating they can be when they surface and how quickly their terror is forgotten after they subside.

During the eruption of Irazu, volcanic dust covered much of Costa Rica's best farmland and some major cities, including the capital, San Jose, less than 20 miles from the crater. The dust, three feet deep in places, caved in roofs, stuck to the tacky leaves of coffee trees and destroyed them, suffocated and poisoned livestock. Even bees died from ash clogging their respiratory systems.

The total damage ran into the western slope of the mountain. A few hundred yards from Calderon's little grocery store in Taras, a small town at the foot of Irazu, massive boulders still litter an area where a rushing wave of water mixed with ash, like liquid concrete, slammed through 300 houses in October 1963 and killed more than 20persons.

But that was 17 years ago. The eruption is now remembered as little more than a spectacle, invariably linked in the minds of Costa Ricans with the coincidental visit of President John F. Kennedy on March 18, 1963, five days after the first eruption and the day clouds of dust began to settle on San Jose.

The volcano, now that it is asleep, is a giant that even the inhabitants of Taras largely ignore. Tourists take buses to its desolately peaceful summit. Dairy cattle graze along Irazu's rich green slopes among Swiss-style chalets.

Some farmers believe that the drainage-enhancing sandy volcanic ash has actually improved the soil. The boulders that helped wipe out so much of Taras are now being used in local construction.

"People have built their houses in the same places they were destroyed," said Calderon. "The people have lost their fear. They moved to high ground during the eruption and swore they would stay there, but now they are moving back."

Not everyone is so complacent, however. Jorge Manuel Dengo, a civil engineer who coordinated Costa Rica's efforts to cope with the Irazu crisis, remembers how ill-prepared the nation was for such a devastating blow. He fears that despite the efforts of the government and the universities to keep a watch on the country's volcanic activity, the history and traumas of Irazu could be repeated.

"A major disaster in one of the Central American countries every two or three years is perfectly predictable," sid Dengo, "and still you always have to improvise."

Dengo recalls the grim uncertainty as to how long Irazu's series of eruptions would continue, the worries that the weak west wall of the mountain would explode -- as St. Helens has done -- and the secret plans for evacuating the entire city of San Jose.

He recounts how some influential Costa Ricans, in desperate ignorance, considered hiring U.S. oilfield firefighter, Red Adair to "put out" Irazu as he might a blazing derrick.

Fortunately the wall of the volcano held fast and the Adair idea was discarded. Much of the information that was eventually gathered at Irazu now may help scientists and engineers in dealing with the St. Helens crisis. n

But Dengo notes a long and persistent record in Central America of failures to recognize -- or meet -- the demands of living in what he calls "the line of fire."

The side of Arenal volcano in northwest Costa Rica, for instance, blew out in 1968 at a time when most people thought it was safely dormant.Two waves of superheated gas rolled across the countryside, killing more than 75 people despite that area's relatively sparse population.

Nevertheless, Costa Rica has since built the nation's largest hydroelectric project within 10 miles of the volcano's summit. Arenal is now constantly monitored, but, as the experience of Mount St. Helens suggests, even the most carefully watched volcano is capable of tremendous and deadly surprises.

There is, however, a positive side to this volcanic energy. Most Central American countries are hoping they may soon turn their restless, molten underpinnings to geothermal sources for energy.

El Salvador already has a working geothermal power plant. Costa Rica hopes to be next. Nicaragua, lacking the hydroelectric potential of its neighbors, is seriously examining the geothermal potential of its Momotombo volcano. Exploration is under way in Guatemala.

Even with the current rather crude technology available, geothermal potential in Central America is estimated at 2.5 million kilowatts.

Among the experts, then, both fears and hopes are running high. But among the people, even here in Taras in the shadow of Irazu, coping with mountains of fire largely means in ignoring them -- until once again, unbidden and controlled, in the words of one resident, "they wake up angry."