The total distance traveled on water and on shore was 2 to three miles. Based on damage observed by Naval Atlantic Meteorology and Oceanography Detachment personnel shortly after the occurrence and reports in the local news, the tornado was estimated to be a strong F0 to weak F1 on the Fujita Scale. The Florida Keys are the greatest natural vortex laboratory in the world. Waterspouts occur more in the Florida Keys than anywhere else in the world, especially from Marathon past Key West on the westward to the Dry Tortugas. The Florida Keys see 400 to 500 waterspouts a year.
Waterspouts moving ashore are a rare occurrence, however.
Water spouts and funnel clouds are most frequently observed in the middle and lower Keys during the late spring and summer months. They tend to occur most often north of the islands, more so than directly over or south of the Keys. Contrary to popular belief, funnel clouds and waterspouts are not always associated with thunderstorms. Waterspouts are most likely to form when the clouds are growing. In the Keys, waterspouts have been observed forming from 7 a. m. through sunset but they most often form between 4 p.m. and 7 p.m., as with the June 18 tornado, with a secondary maximum from 11 a.m. to 1 p.m.