A few months ago, blogging about drought in Ethiopia, I mentioned my definition of drought: "less precipitation than you've come to depend on."
This evening I realized where I'd gotten the idea.
In the August 2002 issue of the Bulletin of the American Meteorological Society, Kelly Redmond wrote a commentary on "The Depiction of Drought." In it, he wrote:
Most concepts of drought involve a water balance. This implies that both supply and demand must be considered, as well as the question of whether there is enough (and, enough for what?). Thus, through time I have come to favor a simple definition; that is, insufficient water to meet needs.