Masters, who runs the Weather Underground, a Web site that provides local forecasts, analyzes severe weather and turns raw storm data from the National Weather Service into captivating maps and data visualizations, has posted a compilation of record and near-record tornado events for 2011. Some notable stats from his post are below. A blow-by-blow description of the year's major tornadoes, as well as a list of the deadliest tornadoes in U.S. history, can be found on NOAA's 2011 tornado review page.
- Six top-end EF-5 tornadoes hit the U.S. in 2011, tying this year with 1974 for the greatest number.
- 2011 ranks third behind 1974 and 1965 for the greatest number of strong to violent EF-3, EF-4 and EF-5 tornadoes.
- Three of the five largest outbreaks on record hit in a six-week period in April and May.
- April 2011 had the most tornadoes of any month in U.S. history: 753. The previous record was 542 in May 2003.
- On April 27, 199 confirmed tornadoes touched down, the largest one-day total on record, beating the 148 that occurred in 24 hours on April 3 - 4, 1974.
- The April 25 - 28, 2011, super outbreak of 343 tornadoes was the largest and most expensive outbreak in U.S. history, according to Masters, causing $10.2 billion in damage.
- The May 22, 2011, tornado in Joplin killed 158 people and injured 1,150, making it the deadliest U.S. tornado since 1947, and the seventh deadliest in history. The $3 billion in insured damages makes it the most expensive tornado in world history.
About the Author: Mark Fischetti is a senior editor at Scientific American who covers energy, environment and sustainability issues.