It's a silly error which in no way undercuts anything in the article afaict, but it annoys because it is very simple and obviously true by unit analysis. I make silly errors too, as we all do, present company excepted. But it does undercut my confidence in the more far difficult journalistic work being done, which I cannot interrogate with my limited mathematical skills and pretty much have to take on faith. To me it speaks to the question of whether I "learned something" or "read some words".
This is a very boring digression and I take full responsibility for making a ticky-tacky point, which I have now I believe fully explained and contextualized.
You could think about what would happen in space (a spherical explosion), then consider what would happen as it got closer to the earth.
>EMT = Y[^]2/3 where Y is in megatons.
>This relation arises from the fact that the destructive power of a bomb does not vary linearly with the yield. The volume the weapon's energy spreads into varies as the cube of the distance, but the destroyed area varies at the square of the distance.
Src: https://www.atomicarchive.com/science/effects/energy.html
It's just geometry, or dimensionality, you cannot directly compare 1D and 2D quantities. Type mismatches are often bad in programming, but always fatal in physics.
Similarly underwater explosions caused spherical and columnar affects depending on yield and depth.