Tornado climatology
The United States averaged 1,274 tornadoes per year in the last decade. April 2011 saw the most tornadoes ever recorded for any month in the US National Weather Service's history, 875; the previous record was 542 in one month. It has more tornadoes yearly than any other country and reports more violent (F4 and F5) tornadoes than anywhere else.
List of tornadoes by province (Canada)
For a variety of reasons, such as Canada's lower population density and generally stronger housing construction due to the colder climate, Canadian tornadoes have historically caused far fewer fatalities than tornadoes in the United States.