Rising 3,432 meters above sea level, Irazú Volcano is the highest point in the Central Volcanic Cordillera. The gently sloping southern flank with its patchwork pattern of potatoes, cabbages, and other vegetable crops, replaced by bucolic dairy farms at higher elevations, belies the violent past of this sleeping behemoth that looms above the city of Cartago.

Upon nearing the summit the destructive forces of volcanism begin to become more noticeable with the presence of scorched dead tree trunks that are still standing. On top of Irazú you will find several deep craters in this barren windswept terrain that is reminiscent of a moonscape. The high elevation itself, being just above the tree line at this latitude, keeps the vegetation from growing very tall, but the periodic devastating effects of eruptions help to keep plant life rather sparse. Among the few species of birds that live in this habitat are the aptly named Volcano Junco and Volcano Hummingbird.

As with all active volcanoes, the level and type of activity changes periodically, often abruptly. Since the last series of eruptions, between August of 1962 and March of 1965, Irazú's principal crater has only emitted fumarole activity -- but things could change again at any time.

To get there: From San José, take the Inter-American Highway east to Cartago, where a good two-lane blacktop road (Highway 8) winds the remaining 34 kilometers up to the volcano's summit.

Climate: You can always spot the real tourists on Irazú, they're the ones wandering around in shirt sleeves and Bermuda shorts -- and shivering to death. Don't be fooled by the fact that Costa Rica is a tropical country, even here it's cold at 3,400 meters (overnight lows below freezing are not uncommon). The wind chill on the summit can add to the sensation, too, so bring along several layers to assure comfort.

The top of Irazú Volcano receives relatively little precipitation, with an annual average rainfall of just over two meters. The driest months are from December to April.

History: The geological history of Irazú Volcano over the past tens of millions of years has been deduced by geologists, but the first written record we have of its volcanic activity only dates back to 1723 when the Spanish Governor of Costa Rica, Diego de la Haya Fernández, chronicled an eruption that began in February of that year. It was a spectacular eruption that threw columns of smoke and ash into the air and sent chunks of incandescent rock rolling down the sides of the volcano, all accompanied by much noise and periodic seismic activity.

Since then, there are accounts of a dozen other eruptions, some equally violent, others milder. The last series of events was from 1962 to 1965.

In August of 1962, Irazú began belching steam, and by early 1963 it was producing such considerable amounts of ash and rock that people living and farming on the upper slopes had to be evacuated. The prevailing easterly winds eventually brought a fallout of volcanic ash over much of the Central Valley, including the capital city of San José. It is said that the ash first began to settle on the city the same day in March of 1963 that the former U.S. President, John F. Kennedy, arrived in town to meet with the presidents of Central America and promote his regional economic development plan known as the Alliance for Progress -- an ominous portent indeed.

For the next two years, ash continued to drift down on the residents of San José and much of the rest of the valley making life very unpleasant and causing eye irritations and respiratory problems for many people. Finally, in March of 1965, this period of volcanic activity subsided, and by 1966 a rock plug had solidified and blocked off the vent -- at least until the next time.