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.
Tornado records
The infamous 1974 Super Outbreak of April 3–4, 1974, which spawned 148 confirmed tornadoes across eastern North America, held the record for the most prolific tornado outbreak for many years. Not only did it produce an exceptional number of tornadoes, but it was also an inordinately intense outbreak producing dozens of large, long-track tornadoes, including 7 F5 and 23 F4 tornadoes. More significant tornadoes occurred within 24 hours than any other week in the tornado record. Due to a secular trend in tornado reporting, the 2011 and 1974 tornado counts are not directly comparable.