The impact of a nuclear weapon on Washington, D.C. would depend on several factors, including the size and type of the weapon, the altitude at which it was detonated, and the local geography and weather conditions.
For example, if a 1 megaton nuclear weapon were detonated at ground level in the center of Washington, D.C., the blast radius would extend for approximately 1.5 miles, while the thermal radiation radius would extend for approximately 3.5 miles. Within the blast radius, virtually all structures would be completely destroyed, while within the thermal radiation radius, fires would be started, and people would suffer from severe burns. Outside of these zones, the radioactive fallout would pose a significant risk to human health and the environment.
If a larger nuclear weapon were used, the effects would be even more devastating. For example, a 50 megaton nuclear weapon (the largest ever tested) detonated at ground level in the center of Washington, D.C. would have a blast radius of approximately 17.5 miles, and a thermal radiation radius of approximately 49 miles. Within these zones, virtually all structures would be completely destroyed, and anyone caught in the blast would be instantly killed. The shock wave generated by the explosion would knock down trees, cars, and other structures up to 100 miles away, while the intense heat generated by the explosion would start fires that could spread for miles.
The radioactive fallout from a nuclear explosion would also be a significant threat. Fallout is the dust and debris from the explosion that becomes contaminated with radioactive material. Fallout can travel hundreds of miles, depending on the wind patterns and weather conditions. The fallout from a nuclear explosion can cause long-term health effects, including cancer and other radiation-related illnesses.
In summary, the impact of a nuclear weapon on Washington, D.C. would be catastrophic, and the exact extent of the damage would depend on several factors, including the size and type of the weapon, the altitude at which it was detonated, and the local geography and weather conditions. Any detonation of a nuclear weapon in a populated area would result in widespread destruction and loss of life, and the long-term effects of radioactive fallout would continue to pose a threat for years to come.