Ninety minutes after the blast, ash began to rain down on Yakima, Washington, a community of fifty thousand people about eighty miles away. As you would expect, the ash turned day to night and got into everything, clogging motors, generators, and electrical switching equipment, choking pedestrians, blocking filtration systems, and generally bringing things to a halt. The airport shut down and highways in and out of the city were closed.
爆发90分钟以后，灰烬开始雨滴般地洒落在华盛顿州的亚基马。那是个有5万人口的社区，离现场大约130公里。正如你可以估计到的那样，灰烬把白天变成了黑夜，钻进了一切物品中，塞住了发动机、发电机和电器，堵住了行人的喉咙，阻塞了过滤系统，总之使一切陷于瘫痪。机场关闭，进出该市的公路封闭。

All this was happening, you will note, just downwind of a volcano that had been rumbling menacingly for two months. Yet Yakima had no volcano emergency procedures. The city's emergency broadcast system, which was supposed to swing into action during a crisis, did not go on the air because "the Sunday-morning staff did not know how to operate the equipment." For three days, Yakima was paralyzed and cut off from the world, its airport closed, its approach roads impassable. Altogether the city received just five-eighths of an inch of ash after the eruption of Mount St. Helens. Now bear that in mind, please, as we consider what a Yellowstone blast would do.
你会注意到，这一切都只是发生在一座火山的顺风地带，而两个月以内那座火山一直在可怕地隆隆作响。然而亚基马没有火山爆发应急程序。该市的紧急广播系统本应在危急时刻快速启用，但是没有出声，因为“星期天上午的工作人员不知道怎么操作这台设备”。有3天时间，亚基马处于瘫痪状态，机场关闭，道路不通，和世界失去了联系。圣海伦斯火山爆发以后，总共只有1.5厘米厚的灰烬落在这个城市。现在，请你把那些记在脑子里，因为我们就要讨论黄石火山的一次喷发会是什么后果。