The entirety of southeast Alaska lay exposed to the Pacific, not encompassed in any of these ADIZ or DEWIZ polygons. Zula guessed that "IZ" must stand for something like "Intercept Zone" and that it was a military designation. She had read about the Distant Early Warning line in a Cold War history class, and so guessed that DEWIZ was Distant Early Warning Intercept Zone and ADIZ was Air Defense Intercept Zone and CADIZ was its Canadian equivalent.