Very impressive blast when you realize that the thing on the side of the mushroom is a battleship pointed straight up.
It was a plutonium fission detonation via implosion. Yield was around 20 kilotons (20,000 tons).
Castle Bravo was 15 megatons (15,000,000 tons)
Had the USS Arkansas been in the same location for a 15 megaton shot it would have ended up, mostly, in the stratosphere. As highly radioactive particles.