I take Joe's point about how how it makes sense in this situation to looking out for all kinds of things. An Almanac could indeed be one of those those - but then so could an umbrella in some circumstances. Or a guitar.

But the bizarre thing here was the way the piece ends "The FBI urged police to report such discoveries to the local U.S. Joint Terrorism Task Force." And the discoveries apparently aren't instances where they were able to identify terrorists by means of the Almanacs they were consulting, but merely instances where they saw someone consulting an Almanac.