An agency that tracks tornado activity is confirming one having touched down near Mine Centre, east of Fort Frances.
The Northern Tornadoes Project says it struck in a remote area to the northeast of the community on July 27th.
A storm that passed over the district the same day caused damage elsewhere and knocked out the power in Atikokan.
The agency says it used satellite imagery to confirm the twister.
It believes it was carrying wind speeds of 190 kilometres an hour and carved out a path of destruction almost 6 kilometres long and 260 metres wide.
Based on the images and damage caused, it has been classified as an EF2 on a scale of intensity.
The tornado is the fourth of its kind confirmed in Canada by the agency this year and the first significant tornado to touch down in Ontario.