Eyewitness Report by Maurice M. Shapiro
INTER-OFFICE MEMORANDUM, 23 July 1945
To: Captain T. O. Jones
From: Maurice M. Shapiro
“During the Trinity test, I was stationed about 20 miles away with the members of the Coordinating Council.
At the time of the initial flash of light, my eyes were not protected, and I was momentarily blinded, much as one would be in emerging suddenly from a dark room into bright sunlight. After a few seconds, I regained good sight to see the entire sky (in the direction of Trinity) aglow with an orange hue. This glow disappeared after a second, and then I saw a column of dark gases rising toward the overhanging clouds. Several people near me commented on the violet color of the shadow of gas, but I observed no such color, presumably because of the initial effect on my eyes. I estimated the gas column’s width (or diameter) as roughly 1/5 mile. After a few minutes, this column rose to a height that I judged to be 8 or 10 miles high; then, it spread laterally. There were a few small puffs of white vapor, which I interpreted as arising from a “cloud-chamber effect” (supersaturation followed by moisture condensation).
The explosion’s shock wave arrived about one and a half minutes after the flash of light, and I heard it as a sharp report. Although I had expected it, the intensity of the blast startled me. My impression at the time was that an enemy observer stationed about 20 miles from the delivery scene would be deeply impressed, to say the least.”
Maurice M. Shapiro