Why don't Altcoins have a timer that ticks down? If blocks aren't solved after 150-200% target time, it immediately lowers difficulty some arbitrary percentage.
It seems like a major weakness. Imagine a power grid failure and most miners in North America can't mine. Will the rest of the world have to just sit there while they cant have their speedy transactions?
I'd be more worried about the nukes/*insert any apocalypse here* used to knock out that many power grids across NA