The destructive range of a nuclear bomb depends largely on the bomb's yield (explosive power) and the type of damage considered (blast, heat, radiation).
- A standard "big" atomic bomb of about 1 megaton yield can cause lethal burns and destruction within about 5 miles (8 km) from the blast, with survivable burns extending up to around 6 miles (9.6 km).
- In terms of area destruction, 1 megaton of explosive power can destroy approximately 20 square miles (about 51.8 square km) of unprotected structures.
- For very large bombs, such as a 50 megaton thermonuclear bomb (Tsar Bomba), the fireball and destructive effects can be visible and felt tens of miles away, with severe damage extending more than 16 miles (26 km) causing leveling of buildings over 2,000 square kilometers (about 772 square miles).
- Intense heat from large thermonuclear explosions can cause severe burns as far as 20 miles from ground zero.
- The blast wave damage radius grows roughly with the cube root of the yield, so a tenfold increase in yield roughly doubles the destructive radius. For example, a 10 megaton bomb might destroy buildings up to nearly 9 km (5.6 miles) from ground zero.
Secondary effects like radiation fallout can contaminate areas hundreds of miles away, far beyond the immediate blast destruction.
In summary, a typical large nuclear bomb can destroy an area with a radius of around 5 miles with deadly effects from blast and heat, and even further for larger bombs and secondary effects. The area of outright destruction for a megaton-range bomb is roughly 20 square miles. For the largest thermonuclear bombs, destruction and fatal effects can extend many tens of miles from the detonation point.
