| The explosive eruptions of Mount Pinatubo in June 1991 injected enormous clouds of volcanic ash and acid gases into the stratosphere to altitudes in excess of 100,000 feet. The largest ash cloud, from the June 15 eruption, was carried by upper level winds to the west and circled the globe in 22 days. The June 15 cloud spread laterally to cover a broad equatorial band from about 10degreesS to 20degreesN latitude and contaminated some of the world's busiest air traffic corridors. Sixteen damaging encounters were reported between jet aircraft and the drifting ash clouds from the June 12 and 15, 1991, eruptions. -- Casadevall, et.al., 1996 |
