The eruption started March 13, 1963, and lasted until February two years later. The economic impact was massive. The Observatorio Vulcanológico y Sismológico de Costa Rica described the impact as chaos.
Ash and other material thrown out by the volcano buried large areas of rich farmland and cattle pasture. But perhaps what was worse was the ash that continued to fall within 50 kilometers mostly to the west of the volcano, including in San José, Heredia and Alajuela. When the rains came, the ash turned to an abrasive mud. Small communities were all but buried.
Central Valley residents shoveled the ash. School kids played in it as if it were sand. Homeowners blocked their windows and doors.
The Observatorio has produced two videos about the volcano. One is a commemorative, and the second is historic footage of the impact.
The volcano has been emitting acidic gases for the last three years. Much of the farmland there now shows the deadly effects of the gas. Brush has died and trees are stripped of their leaves. The same is true of the nearby sister volcano Turrialba, which also is in an active phase. Both are east of San José, and Irazú can be seen from the downtown 25 kilometers (15.5 miles) away.
Five days after the mountain began its eruption, then-U.S. president John F. Kennedy came to San José for a meeting with heads of Latin states. Videos of Kennedy’s arrival by helicopter in what is now Parque la Sabana and a motorcade up Paseo Colón do not show a lot of ash. Most of the capital’s 250,000 residents lined the streets to greet him, and the day appeared to be sunny, Most wore white.
That also was true two days later when Kennedy spoke to a massive crowd at the newly inaugurated Universidad de Costa Rica. The crowd seemed unaffected by ash. But a reporter who was with the president said that by day’s end the ash had soiled shirt collars and other parts of the clothing.The big question in the minds of most residents is can the same type of eruption happen again.
The Red Sismológica Nacional at the Universidad de Costa Rica has anticipated this question on its Web page. The volcano scientists say that it is unlikely that the country could be taken by surprise the way it was 50 years ago. Technology has created a number of monitoring devices that keep close watch on this mountain and the other active volcanoes in the country, it said. In addition, the Red added, the signals that are coming from the volcano now do not indicate that there will be an eruption in the near future.
The volcano eruption had a lot of unanticipated consequences. For example, a study of insects showed that honey bees were decimated by ash being in the nectar that they collected. That wasthe result of a study published in 1975 by Alvaro Wille and Gilbert Fuentes, entomologists at the Universidad de Costa Rica. They also found that certain insects with waxy exteriors thrived and even became economic pests because their natural enemies had been eliminated.
At times the erupting mountain was a tourist attraction, and a photo by long-time San José photographer Francisco Coto shows visitors to the volcano with a gigantic eruption in the background.
The photo was part of a show at the Museo Nacional in 2011.