The map above simulates a 300-kiloton nuclear airburst over Chicago, USA — roughly the size of a modern deployed warhead. The coloured rings show the estimated fireball, the zones of heavy, moderate and light blast damage, the reach of the thermal flash and the ionizing-radiation dose. Drag the marker or change the weapon in the full simulator to explore other scenarios.
The metropolitan area is home to about 9.4 million people — the rings above are drawn to real scale over their homes.
The marker is on the Loop. The 1.9 km zone of total destruction covers Willis Tower, Millennium Park, the Art Institute, Union Station and the River North high-rises; the 4.7 km collapse ring reaches Navy Pier, the Near West Side, the South Loop, the United Center's approach and Old Town. Third-degree burns extend to about 7.5 km over Lincoln Park's southern half, Pilsen, Bronzeville, the Illinois Medical District and Wicker Park; the 14.5 km ring of broken windows reaches Wrigley Field, Hyde Park, Logan Square, Cicero's edge and Garfield Park.
Chicago's 2.7 million residents are strung along the lakefront, so about half of every ring falls on Lake Michigan — a real attacker would likely shift the aim point inland. The city is flat prairie with no terrain shadow. Chicago was where the first controlled chain reaction took place, under the stands of Stagg Field in December 1942; see How nuclear weapons work. The 800-kiloton scenario shows a larger single warhead.
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