It has been a long time since most of those places have been cold enough, long enough, to have a lake become that solidly frozen. It has been 30+ years since I have seen this happen in the mid atlantic.
I think by "mid Atlantic" they mean a city in the US on the Atlantic coastline, but not the northern tip of the country, or the southern end. The mid part. But they're talking about lakes or rivers in those areas, not the ocean itself.