As the Canadian city with the highest number of days that experience severe thunderstorms and lightning, Windsor has historically been subject to tornadic activity. The strongest and deadliest tornado to touch down in Windsor was an F4 in 1946. Windsor was the only Canadian city to experience a tornado during the 1974 Super Outbreak, an F3 which killed nine people when it destroyed the Windsor Curling Club. The city was grazed by the 1997 Southeast Michigan tornado outbreak with one tornado (an F1) forming east of the city. Tornadoes have been recorded crossing the Detroit River (in 1946 and 1997), and waterspouts are regularly seen over Lake St. Clair and Lake Erie especially in autumn.