User blog comment:Argorrath/Sledgehammer Games claims to be working on a new MW game/@comment-90.215.115.170-20130718213054/@comment-1840877-20130719143038

My theory for that is that the EMP itself was more localised, and that the blackout spreading across the coast like we saw in "Second Sun" was the result of an overload on the electrical grid, a bit like the blackout in the northeast US and Canada in 2003. Once the techs got things re-routed, they could just bring the rest of the grid back online. It's not the best explanation, but it's the best I can think of.