If a wartime atomic bomb yielded like Tsar Bomba

What if Little Boy or Fat Man suddenly produced a Tsar Bomba-scale yield after release?

The target would be devastated on a vastly greater scale, the B-29 would probably be lost, and the unexplained yield difference would complicate assessment of both attacks.

A Tsar Bomba-scale yield from Little Boy or Fat Man would cause destruction far beyond the historical attack. The B-29 would be very unlikely to escape, removing the aircrew and much of the photographic or observational evidence used to assess the strike. A huge difference between the two wartime detonations would create uncertainty over whether the weapon worked as intended and why the other bomb behaved differently. Castle Bravo is invoked as a later example of a yield greatly exceeding expectations, while the scenario remains explicitly counterfactual.