Nuclear explosions are similar to conventional explosions to the extent that their immediate destructive action is due mainly to air blast or shock.

The rapid release of energy within a small enclosed space causes a considerable increase in temperature and pressure. All materials present within this space are converted into hot, compressed gases. These highly compressed gases expand rapidly, causing a shock wave in the surrounding medium (i.e., air, water, or earth).

The shock wave drives air away from the center of the explosion. This action produces sudden changes in air pressure that can crush objects and create high winds that can knock people and structures down.

The shock wave is characterized by a sudden increase in air pressure at the front, followed by a gradual decrease.