This is the second in a series of articles that seek to quantify just how bad this year's tornadoes were in a historical context. It wasn't just media hype!
In a previous article I wrote that the late April tornado outbreak was so severe that it merited the special name "Superoutbreak 2011." That's just the second time that a tornado outbreak has earned that title, the first being on April 3-4, 1974.
This article focuses on three of the individual tornadoes from the spring of 2011 that rank among the worst on record in the United States. Two of them came on April 27 during that Superoutbreak 2011: an EF4 tornado that hit Tuscaloosa and Birmingham AL along an 80-mile path, and an EF5 tornado that hit Phil Campbell and Hackleburg AL along a path that was over 106 miles long and continued into Tennessee. The third was an EF5 tornado that hit Joplin Missouri on May 22.
These were the three deadliest tornadoes in the United States since 1957, when radars began to be widely used for storm detection in the United States. At that time the National Weather Service was called the Weather Bureau, and the radars did not have any Doppler wind information. The Joplin tornado caused at least 159 deaths. The Hackleburg tornado killed at least 72, and the Tuscaloosa tornado killed at least 64. The Joplin tornado was the deadliest since a tornado hit Woodward, Oklahoma in 1947.The table below lists the 20 deadliest tornadoes on record in the United States. Joplin stands as the only tornado on the list since 1953, the year that the Weather Bureau began to issue tornado forecasts. The worst was the Tri-State (MO, IL, IN) tornado on March 18, 1925 that killed 695 along a 219-mile path, the longest on record.
In raw dollars (i.e., costs at the time that they occurred), these were also the three costliest tornadoes on record in the United States. Estimated costs from the Joplin tornado are $2.8 B (billion), $2.2 B from the Tuscaloosa tornado and $1.25B from the Hackleburg tornado. The previous record holder in raw dollars (not adjusted for inflation), was the F5 tornado that hit Moore, Oklahoma and Oklahoma City on May 3, 1999, with loss of $1 B.
Of course, because of inflation it isn't fair to compare raw costs from a tornado today to one that occurred decades ago. For that reason, I've attempted to "normalize" the costs into 2011 dollars. To do that I've used economic statistical measures called "Fixed Reproducible Tangible Wealth" or "wealth" from 1929 to 1995, and "Gross Domestic Product" for years when "wealth" data weren't available. This is just one way to do it, but follows in the tracks of a
http://www.nssl.noaa.gov/users/brooks/public_html/papers/damage.pdf previous study by colleagues Harold Brooks and Chuck Doswell. Results are in the table below.
Even with the adjustment for inflation of older tornadoes, Joplin still ranks as the costliest tornado. With the dramatic effects of the adjustment for inflation, the St. Louis tornado of 1896 zooms from a raw cost of $12 million to $2.558 billion to take second place. The Tuscaloosa and Hackleburg tornadoes from Superoutbreak 2011 take third and thirteenth places, respectively. From the 1974 Superoutbreak, only the F5 Xenia, Ohio tornado cracks the top 25.
Combining deaths and damage to come up with a ranking of worst tornadoes is definitely a very subjective and arbitrary process. What I've done is to give the deadliest tornado (Tri-State tornado of 1925) 50 points and then scale other tornadoes on their percentage of that tornado's death toll. Similarly, I've given 50 points to the Joplin tornado for its 2.8 billion dollars in damage, and then scaled other tornadoes based on their adjusted damage cost values. There would be a maximum score of 100 if a single tornado had highest values in each category, which wasn't the case. Values and rankings are shown in the table below.
Using that ranking scheme, the Joplin tornado of 2011 winds up third-worst tornado on record in the United States. It follows the Tri-State tornado of 1925 and the St. Louis tornado of 1896. The Tuscaloosa tornado comes in fourth and the Hackleburg tornado comes in eighth.
An interesting result is that, despite earning the first classification as a "Superoutbreak", none of its tornadoes on April 3-4, 1974 ranked in the top 25 individual worst ones. By contrast, the 2011 Superoutbreak had two of the top 25 worst tornadoes. The 1974 Superoutbreak had more killer tornadoes, but the most deaths from an individual tornado were 34 from the Xenia, OH tornado. That death toll was so far down on the list (and not on the top table) that it kept it (and other tornadoes from 1974) off the "worst tornado" list.
In summary, 2011 brought one of the two worst tornado outbreaks on record in the United States and three of the worst individual tornadoes. It also brought six tornadoes (thus far) given the top rating of EF5. The only other year which had that many was 1974. 2011 truly was a remarkable year!
