The Gretna storm of June 8, 2005
A supercell thunderstorm formed in northern North Dakota on the evening of June 8, 2005. As it approached the Canadian border, it increased in intensity and produced a tornado just southwest of Gretna, MB. On the Canadian side of the border it produced funnel clouds and quarter-sized hail. The interesting part about this storm is that it was rotating anticyclonically, a trait of very few supercells.
The RADAR images from this event are on this page.