 Data and observations began to accumulate that debunked Stormfury's working hypothesis. Beginning with Hurricanes Anita and David, flights by Hurricane Hunter aircraft encountered events similar to what happened in "successfully" seeded storms. Anita itself had a weak example of a concentric eyewall cycle, and David a more dramatic one. In August 1980, Hurricane Allen passed through the Atlantic, Caribbean, and Gulf of Mexico. It also underwent changes in the diameter of its eye and developed multiple eyewalls. All this was consistent with the behavior that would have been expected of Allen had it been seeded. Thus, what Stormfury was accomplishing by seeding was also happening on its own.
