Once volcanic ash is released by an eruption and becomes airborne, its movement is outside the direct jurisdiction of all concerned agencies, including the Federal Aviation Administration, the U.S. Geological Survey, and the National Oceanic and Atmospheric Administration. Soon after the successful prediction of the December 14, 1989, eruption of Redoubt Volcano many hours before it actually occurred, we learned that a KLM Boeing 747 nearly crashed as it encountered the ash cloud over the Alaska Range (see Figure 1). This accident occurred even though all concerned agencies in Anchorage were notified of the predicted and actual eruption by the Alaska Volcano Observatory.