If you want to look for something that would validate the OP's assertions, I would look for severe shortages of food that go on for more than a month. I would say that were there more than 1-2 weeks with widespread (multiregional) shortages or widespread unavailability of food and/or fuel.
Of course, that doesn't mean you shouldn't prepare for the worst. If this next sign comes to pass, and you aren't already at least MOSTLY ready, you're probably going to be too late. I, for one, am preparing for the worst, but hoping for the best (in that order). I'm not quitting my day job, however.