Abstract
Radiochemical measurements of 7Be were carried out for a total of 246 individual rain and snow samples collected at Fayetteville (36°N, 94°W), Arkansas, during the period between September 1979 and December 1984. A sharp increase in the 210Po/7Be ratio in rain observed during the winter and spring months of 1980-1981 was attributed to the fallout of excess 210Po from the May 1980 eruption of Mount St. Helens.