Lot of those in your closet? Because, in the 60’s, nobody had one.
11/1/52 US explodes hydrogen bomb at Bikini Atoll yield=10.4 MT
1954-US test bomb yield is almost 17 MT
11/22/55 Russia explodes bomb in Kazakhstan 1.6 MT yield
11/8/57 Britain explodes bomb yield = 1.8 MT
10/31/61 Russia explodes bomb yield=58MT
By the early sixties, bombs with yields greater than 1MT were not unknown.
The yield were closely guarded secrets, and the effects could only be guessed at.