| Damage (U.S.) | Unknown |
|---|---|
This page documents the tornadoes and tornado outbreaks of 1939, primarily in the United States. Most tornadoes form in the U.S., although some events may take place internationally. Tornado statistics for older years like this often appear significantly lower than modern years due to fewer reports or confirmed tornadoes. Also, prior to 1950, tornadoes were not officially surveyed by the U.S. Weather Bureau, which would later become the National Weather Service, and thus had no official rating. All documented significant tornadoes were instead given unofficial ratings by tornado experts like Thomas P. Grazulis.