Dozens of people were killed over the weekend when a fierce storm system spawned tornadoes across seven U.S. states. Despite accurate forecasts, the sheer number of tornadoes, their strength, and their prolonged time on the ground made this a devastating event. Read more: http://www.cbc.ca/news »»» Subscribe to CBC News to watch more videos: http://bit.ly/1RreYWS Connect with CBC News Online: For breaking news, video, audio and in-depth coverage: http://bit.ly/1Z0m6iX Follow CBC News on TikTok: