Wisconsin may be hundreds of miles from the nearest intercontinental ballistic missile silo, but new simulations from a University of Wisconsin-Madison researcher suggest the state would still be in the firing line of radioactive fallout if the Great Plains missile fields were ever hit. The work uses weather data and mushroom-cloud dispersion models to show how contaminated soil and debris from ground-level nuclear explosions could hitch a ride on fast upper-level winds and drift straight into the Midwest. The timing is not exactly comforting: the findings arrive just after the New START nuclear treaty expired on Feb. 5, reopening a long-simmering debate over how to handle modern nuclear risks, as reported by The Missiles on Our Land.
Those fallout maps and hundreds of daily scenarios are part of Princeton University’s project The Missiles on Our Land, which modeled attacks on missile silo fields using 2021 weather patterns to trace where radioactive particles might fall. According to the project, a sustained strike on the silo fields could send fallout across large swaths of the continental United States and into Canada and Mexico, with the footprint shifting day by day with wind and rain.
What the models show
Sébastien Philippe, an assistant professor at UW-Madison who helped build the simulations, told Wisconsin Public Radio that "the probability of nuclear war may be small, and although it's small, it's probably higher than it has been in a long time." His team focused on attacks aimed at hardened silo fields, which he said would likely rely on low-altitude detonations that vaporize soil and concrete, then loft the contaminated mix into powerful upper winds capable of carrying fallout hundreds of miles.
In the models, that toxic dust does not respect state lines. It spreads, curls and shifts with the atmosphere, landing in places that are nowhere near the initial targets, including Wisconsin.
Why the Midwest is vulnerable
The United States keeps roughly 400 deployed Minuteman III intercontinental ballistic missiles in underground silos in Montana, North Dakota, Wyoming, Nebraska and Colorado, according to the Center for Arms Control and Non-Proliferation. Because those missiles sit in fixed, heavily reinforced structures, taking them out would require multiple detonations close to each site.
That is exactly the kind of strike that produces the worst fallout. Ground-level or low-altitude nuclear blasts scoop up enormous amounts of soil and building material, turning them into radioactive particles that can be carried long distances. The Princeton project uses that scenario to feed its simulations, which then track the resulting plumes as they ride the wind across the country.
What it could mean for Wisconsin
Princeton's simulations estimate that a concentrated attack on the silo fields could lead to U.S. casualties in the hundreds of thousands to the millions, with an average national death toll of roughly one to two million depending on weather and how well people shelter. For Wisconsin, the interactive maps show a range of unsettling possibilities in which farms, small towns and city neighborhoods land under heavier fallout, depending entirely on the atmosphere’s mood that day.
On some modeled days, the state takes only a glancing hit. On others, thick plumes drift directly overhead. The message is less about pinpoint prediction and more about vulnerability: in a large nuclear exchange, Wisconsinites could face serious fallout even if no one targets anything in the state.
Policy context and what’s next
The policy backdrop has grown more tense since New START expired on Feb. 5, 2026, a development reported by AP News. The lapse removed caps and some verification rules that had applied to the two largest nuclear arsenals on the planet. Analysts and commentators have warned that losing that transparency could speed up nuclear modernizations and strategic gambits, making fallout-mapping work like Philippe’s feel a lot less theoretical, as noted in Phys.org.
Philippe’s research has not stayed confined to academic journals. He was named a 2025 MacArthur Fellow and is one of 21 scientists serving on the United Nations Independent Scientific Panel on the Effects of Nuclear War, which the U.N. Office for Disarmament Affairs says will deliver a report to the General Assembly in 2027.
That mix of campus modeling, public reporting and U.N. review is turning what used to be an abstract Cold War debate into something far more concrete for states like Wisconsin. The upshot of Philippe’s work is stark enough: decisions about arms control, silo fields and nuclear strategy do not just affect the Great Plains, they shape the risks facing anyone who lives downwind.
