Scenario: The Great Freeze
It started with a freak storm system that brought sub-zero temps and gale-force gusts. Next thing you know, the polar bears are migrating to your neighborhood.
As the ice sheets spread, the government declares martial law, but it's too late. The polar bears have already eaten all the good snacks.
You're left with a choice: flee to Canada or stay and fight for your right to a warm bed.