The Totskoye nuclear exercise was a military exercise undertaken by the Soviet Army to explore defensive and offensive warfare during nuclear war. The exercise, under the code name “Snowball” (Russian: Снежок, romanized: Snezhok), involved an aerial detonation of a 40 kt[1] RDS-4 nuclear bomb. The stated goal of the operation was military training for breaking through heavily fortified defensive lines of a military opponent using nuclear weapons.[2][3] An army of 45,000 soldiers marched through the area around the hypocenter soon after the nuclear blast.
From 1949 to 1989, residents of the former Soviet oblast of Semipalatinsk lived under the shadow of a mushroom cloud. Over that time, at least 456 nuclear devices – both atmospheric and underground – were detonated at the 18,000-square-kilometer site known as Semipalatinsk-21.