These are some notable tornadoes, tornado outbreaks, and tornado outbreak sequences that have occurred in North America. 1. * The listing is U.S.-centric, with greater and more consistent information available for U.S. tornadoes. Some North American outbreaks affecting the U.S. may only include tornado information from the U.S. 2. * Exact death and injury counts are not possible, especially for large events and events before 1950. 3. * Prior to 1950 in the United States, only significant tornadoes (rated F2 or higher or causing a fatality) are listed for the number of tornadoes in outbreaks. These ratings are estimates from tornado expert Tom Grazulis and are not official. 4. * Due to increasing detection, particularly in the U.S., numbers of counted tornadoes have increased marked