We're at the southern end of that chain. We did it at school in the early '60s.My mom remembers in the 50's they used to do Duck and Cover here in Winnipeg. It was a real fear because we're a central transport hub in North America and the soviets could have just flown over the north pole to bomb us. Kill us and stop the flow of supplies. I don't know if it's still as valid today as it was back then, but it is a sobering thought.
It's been ridiculed a lot lately but we were concerned with atomic bombs, not thermal nuclear. If those hit 10-20 miles away you had a chance.