Morton Salt, a company that packages and sells salt, used this as it's slogan. As most of you know, humidity causes salt to clump. When the salt clumps it won't pour from the shaker. Morton claims that their special blend of salt won't clump when the humidity rises (though I can't imagine what they do to the salt to prevent clumping). My father is under the impression that Morton Salt created this expression, and a lot of people misinterpreted it to mean: "When things are bad, they're going to be as bad as possible." That doesn't really make much sense to me. I think this has been an expression long before Morton Salt used it, and the company realized that the slogan applies to their product, when interpreted differently.