National Geographic : 1981 Jan
Night fell at midmorning on Yakima (above), in stark contrast to the view on a clearday (below). May 18 dawned a brightSunday morning-untilabout9:30 a.m., when an ugly black cloud swept in from the west. Unalertedto the eruption 85 miles away, residents braced for a thunderstorm.What fell instead resembled soft sand. More than half an inch blanketed the city, precipitatinganxiety and bewilderment: Was it dangerous to humans? Crops? How to get rid of it? At first, no one knew.