The reach of a nuclear bomb depends on its size and yield, but here are some key ranges based on a typical 1-megaton bomb (which is much larger than the Hiroshima bomb):
- Immediate vaporization occurs at the blast center with temperatures reaching 100 million degrees Celsius.
- Third-degree burns can affect people up to about 8 kilometers (5 miles) away.
- First-degree burns up to about 11 kilometers (7 miles).
- Flash blindness can occur up to 21 kilometers (13 miles) during the day and even farther at night (up to 85 kilometers or 53 miles).
- The shockwave can flatten buildings within about 6 kilometers (3.7 miles), with deadly wind speeds reaching up to 750 kilometers per hour near the center.
- Radiation fallout from a ground-level detonation can spread toxic particles for hundreds of miles.
Lethal structural destruction extends roughly 1 mile radius for severe damage and can cause moderate to light damage several miles beyond that depending on the bomb yield. For example, a 1 megaton bomb can cause severe damage up to around 1 mile and moderate damage out to 5 miles or more.
Larger bombs with yields in the tens of megatons can cause severe damage and burns over tens of kilometers. For example, a 10 megaton bomb can produce severe blast damage out to 8.6 kilometers (5.3 miles).
In summary, the "reach" of a nuclear bomb in terms of lethal blast, burns, and radiation can extend from about a few kilometers to tens of kilometers depending on the bomb size, with fallout spreading contamination for hundreds of miles beyond the blast site.
