G7-Mt. Pinatubo-Approcahing-04

The teams knew they had to be careful. The timing of an evacuation needed to be right on the mark. If an evacuation was ordered too early, people may start to return to their homes if an eruption did not happen within days. They knew if that happened, the team would lose the trust of the people. They would not get a second chance to order another evacuation. Two days before the first eruption occurred, the evacuation was ordered. For the first five days, lava belched out of Pinatubo. On June 12, that all changed with a series of larger eruptions.

The largest of the ejections occurred on June 15. On that one single day, over 1 cubic mile of material erupted from the volcano. It reached heights of 22 miles into the sky. Torrents of searing hot ash, gas, and pumice fragments (pyroclastic flows) poured down the flanks of the mountain. The debris filled the once-deep valleys, filling them with as much as 660 feet (200 meters) of fresh volcanic deposits. Unfortunately, as one disaster subsided, another one was just starting.

What are the odds of having a volcanic eruption and a typhoon on the same day? It sounds crazy, but that is exactly what happened. The two disasters compounded the devastation. Typhoon Yunya struck the island. The typhoon’s torrential rains, mixed with the ash deposits, caused massive lahars. A lahar is a giant mudflows of volcanic debris. An eruption on the scale of Pinatubo can deposit huge amounts of volcanic ash and pyroclastic debris. When this debris gets wet, the volcanic debris turns into a fast moving, concrete-like slush.

A lahar can actually flow faster than clear water. It knocks down everything in its path. Fortunately, for the people of the area and those stationed at Clark Air Force Base, the scientists’ work helped to save thousands of lives. Most of the deaths (more than 840 people) and injuries from the eruption were from the collapse of roofs under wet, heavy ash. Many of these roof failures would not have occurred if there had not been a typhoon. For you, it was the chance of a lifetime. It was what made your career what it is today. You look over at your cell phone and wonder when you will get the next call.