High Altitude EMP

Any nuclear detonation above 25 miles will cause a high altitude EMP (electromagnetic pulse). A nuclear weapon detonated at an altitude of 200 miles could affect all unprotected electrical equipment within the continental United States. Nuclear weapons at that altitude could be detonated from a satellite, an intercontinental ballistic missile, or from a ‘Scud’ type missile launched from a freighter. Depending on the location and size of the blast, the effect would be to knock out the power grid across most, if not all, of the continental United States.



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