[D_Idaho]

There’s a very excellent documentary available called “Trinity and Beyond” that documents the US nuclear test programs up until the Nuclear Test Ban Treaty. Part of it shows the high-altitude tests conducted at Johnston Island. One of them knocked out power over a large area of the pacific from the EMP effect. Those were the days!

[IndispensableDestiny]

Part of it shows the high-altitude tests conducted at Johnston Island. One of them knocked out power over a large area of the pacific from the EMP effect.

Starfish Prime (the article) was launched from Johnston Atoll. It had the effects you mentioned.