So much for the “Years of Living Dangerously“
Dr. Roger Pielke Jr writes in the WSJ:
So far in 2014, the United States has experienced fewer tornadoes than in any year since record-keeping began in 1953, or even before. Greg Carbin, a meteorologist with the Storm Prediction Center of the National Oceanic and Atmospheric Administration, has called this “likely the slowest start to tornado activity in any year in modern record, and possibly nearly a century.” But just because tornado activity has declined doesn’t mean that we can let down our guard, as potentially large impacts are always a threat.
Overall, however, the good news for residents of the Midwest’s “Tornado Alley” and elsewhere is that over the past six decades America has witnessed a long-term decrease in both property damage and loss of life. That’s the finding that I and Kevin Simmons and Daniel Sutter, two of the nation’s leading tornado experts, have gleaned from studying the data on almost 58,000 tornadoes observed since 1950.
Using estimates collected by the NOAA’s Storm Prediction Center, we used several approaches, including taking inflation into account, to “normalize” historical losses to 2014 dollar values in order to estimate how much damage would occur if tornadoes of the past occurred with today’s levels of population and development.
The average annual U.S. property losses caused by tornadoes, from 1950 to 2013, is $5.9 billion in today’s dollars. However, for the first half of the data set (1950-81), the annual average loss was $7.6 billion, and in the second half (1982-2013), it was $4.1 billion—a drop of almost 50%.
Does the substantial decline in average annual damage mean that there have actually been fewer tornadoes? Not necessarily. The U.N.’s Intergovernmental Panel on Climate Change concluded recently that the quality of the available data on tornado frequency and intensity makes drawing conclusions about long-term trends problematic: “There is low confidence in observed trends in small spatial-scale phenomena such as tornadoes and hail.”
What we can say with some certainty is that the number of years with very large tornado losses has actually decreased. Consider that from 1950 to 1970 the U.S. saw 15 years with tornado damage in excess of $5 billion a year. From 1993 to 2013 there were only four such years, with three since 2008.
Full story here at the WSJ