I think it's meant to focus on urban areas and military installations. 50% of the US population lives in 1% of the area, so around 240,000 square km, and that w

I think it's meant to focus on urban areas and military installations. 50% of the US population lives in 1% of the area, so around 240,000 square km, and that would cover almost all of the decision makers, wealthy people, politicians, supply chain centers, etc. Then there is the resulting civilization breakdown and weather conditions for the rest of the population.