Terry’s Take: 2011 The year of the tornado!
Tornado statistics are like baseball statistics. There are many ways to describe a season and the performance (or lack thereof) from the players. Unlike baseball, however, tornadoes and the atmosphere play by rules that we do not completely understand. The impacts that tornadoes have on mankind are determined by demographics and underlying vulnerability, factors that are difficult to predict and track. The fact that weather is highly variable allows us to state unequivocally that the tornadoes of 2011 were unlike any tornadoes that came before, and will remain different from tornadoes in the years ahead. Six EF5 storms and 550 fatalities, including 160 in the historic Joplin twister made 2011 unprecedented in the modern era of tornado forecasting (1950 to the present). Hopefully, lessons learned and historical analogs to the 2011 tornado events can provide insight into how often significant tornadoes, and especially significant tornado outbreaks, might occur in the future.
For people from Oklahoma to Arkansas and Missouri, and from Mississippi to Alabama, Georgia, Tennessee, North Carolina, Virginia, and even Massachusetts, 2011 will be remembered as a year of catastrophic devastation, and unfortunate and untimely death. Even for seasoned severe-storm forecasters, the events of 2011 are sobering and difficult to place in historical context. In 2011, 550 people lost their lives to 59 killer tornadoes. This makes 2011 the fourth-deadliest year for tornadoes in recorded history. Only 1925, with over 700 deaths; 1936, with 552 fatalities; and 1917, with 551 deaths, exceed the stark death toll of 2011. Over the past 50 years, the United States has averaged 72 tornado deaths from 22 killer tornadoes per year. The 59 killer tornadoes of 2011 are surpassed only by the 73 killer tornadoes of 1974. The 2011 events that culminated in an eightfold increase over the average annual number of tornado fatalities, and the historical significance of 2011, will be studied and discussed for years.
Annual tornado fatality figures have shown a steady decrease in the last century. Enhanced understanding of severe weather meteorology, and subsequent advances in forecasts and warnings, as well as significant improvements in detection and communications technologies, have all surely contributed to the downturn in tornado deaths in the United States. So why were the tornadoes of 2011 so deadly? One explanation is that, like category 5 hurricanes striking the U.S. mainland, widespread and violent tornado outbreaks are infrequent meteorological events—perhaps even more infrequent than major hurricanes striking the United States mainland. Even with impressive advances made in forecasting and warning for these events, no technology currently exists to change the formation, intensity, or track of the most locally extreme examples of severe weather on Earth—tornadoes.
There were 1,690 tornadoes reported across the United States in 2011. This annual total is exceeded only by 2004 when 1,817 tornadoes occurred. There were tornadoes in 48 states in 2011, with only the largest state (Alaska) and the smallest state (Rhode Island) recording no touchdowns. The only other year when 48 states had at least one tornado recorded was 1989. Tornadoes occurred on 179 days in 2011 and, despite being a prolific year in other ways, this daily count is very close to the 50-year average of 177 days per year with at least one tornado reported. The year with the most tornado days (211) was 2001.
The ferocity and violence of the tornadoes during 2011 make the year stand out as one of the deadliest and most destructive in U.S. history. Many people may have been surprised at such widespread tornado destruction occurring in the modern era. But history provides examples of what happens when the atmosphere mixes the necessary ingredients together for widespread and deadly tornado outbreaks. These extreme events may only occur once or twice a generation, over relatively modest-sized areas of the United States, if we are lucky. There is high confidence, however, that the more significant events can be anticipated to some degree, at least a few days in advance, despite the continuing elusive and deadly nature of individual tornadoes.
Some of the unfortunate United States tornado records in 2011 include the second greatest annual number of tornadoes (1,690), the second greatest annual number of tornado injuries (5400), and the fourth deadliest year for tornadoes (550) in U.S. history. Given these figures, it is difficult to find adjectives that adequately describe the tornadoes of 2011, and the impacts those tornadoes had on people’s lives. From my perspective, 2011 was the year of the tornado!