The Elie, MB tornado of June 22, 2007 (image left) has been re-classified as an F5 tornado, upgraded from its original F4 rating. This makes the Elie tornado Canada's first officially documented F5 tornado. The re-classification was based on re-analysis of the video data, including video of a home being completely swept off its foundation and obliterated in mid air as well as a heavily loaded van being thrown a considerable distance. (see video here) According to the Fujita tornado rating scale, this type of damage is consistent with an F5 tornado with wind speeds of 400-500 km/h. For further details on the Elie, MB tornado.. see my earlier June blog entries.
Note that tornado ratings are based on the most intense damage found within the track of that tornado. It doesn't mean the tornado was always at F5 strength, but that it reached F5 at its maximum intensity. Note also that tornado strength is based on physical damage caused by the tornado. If a powerful tornado doesn't hit or damage anything, than it can only be classified as an F0 tornado.. no matter how strong it really may have been. As a result, there may have been other tornadoes in Canada that were F5 strength at some point, but they didn't hit any structures during that time to warrant an F5 rating. The Pipestone tornado that hit a day after Elie is a good example of this. This monster tornado is officially rated as an F3, however it didn't hit anything structural at its maximum intensity, staying mostly over open fields and forests at its height (good thing too!)