Castle Bravo: 15 MT Thermonuclear Explosion!
This cloud, at various stages in its development, showed
four
condensation rings, three ice caps, two skirts, and three bells.
The three ice caps and two of the condensation rings are visible
in this photo (DNA22-DPY-7-15)
Photo Source: Chuck Hansen's book:
"U.S. Nuclear Weapons, the Secret History", 1998, pg 113