JOPLIN, Mo. — Greg Forbes, the severe-weather expert with The Weather Channel, has crunched the numbers to offer a convincing argument that the May 22 tornado in Joplin was the third worst on record in U.S. history.

To reach that conclusion, Forbes examined both the loss of life and the loss of property.

“It’s open to a little bit of argument,” he said in a recent phone interview from his office in Atlanta. “Identifying the worst tornado based on cost and number of deaths is a very subjective and arbitrary thing.

“If not No. 3, I certainly think it can be justified that the Joplin tornado is in the top five.”

Forbes, whose blog about Joplin and “Superoutbreak 2011” can be read at www.weather.com/blog/weather/8_25880.html, puts what happened in 2011 into historical context to dispute those who might think that this year’s severe weather was “just media hype.”



2011 NUMBER

Forbes, who studied under the late T. Theodore Fujita, creator of the Fujita Tornado Scale, said 2011 brought one of the two worst tornado outbreaks on record in the United States and three of the worst individual tornadoes.

Six tornadoes in 2011 were given the top rating of EF-5. The only other year that had as many was 1974, the year of the first so-called superoutbreak.

Superoutbreak 2011, Forbes contends in his blog, might in some ways be worse than what happened in 1974. He writes: “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, Ohio, tornado.”

There were three devastating tornadoes in 2011 that killed at least 297 people combined. Two of them came on April 27: an EF-4 tornado that hit Tuscaloosa and Birmingham, Ala., along an 80-mile path, killing 64 people, and an EF-5 tornado that hit Phil Campbell and Hackleburg, Ala., along a path more than 106 miles long, killing 72 people. The third — and the worst, Forbes contends — was the EF-5 tornado that hit Joplin on May 22, killing 159 people, which is the official death toll of the National Weather Service. The agency did not include two deaths in which the tornado was not the direct cause of the fatality. The local count stands at 161.



RADAR USE

Forbes said: “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. The Joplin tornado was the deadliest since a tornado hit Woodward, Okla., in 1947.”

In the early days, the National Weather Service was called the Weather Bureau. The radar in use then did not have Doppler wind information.

On Forbes’ list of the 20 deadliest tornadoes on record in the United States, Joplin is the only entry since 1953, the year that the Weather Bureau began to issue tornado forecasts, he said.

In dollars, the three significant 2011 tornadoes were the three costliest on record in the United States, Forbes said. Estimated costs for the Joplin tornado are $2.8 billion. Costs are estimated at $2.2 billion at Tuscaloosa and $1.25 billion for Hackleburg. The previous record holder in raw dollars — not adjusted for inflation — was the tornado that hit Moore, Okla., on May 3, 1999; damage was estimated at $1 billion.

To compare the tornadoes with those of the past, Forbes normalized the costs with statistical measures that adjusted for inflation.

Said Forbes: “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 $2.55 billion to take second place. The Tuscaloosa and Hackleburg tornadoes take third and 13th places, respectively.”

Forbes then combined the number of deaths and the amount of damage to come up with a ranking of worst tornadoes. The worst was the Tri-State Tornado on March 18, 1925. It killed 695 along a 219-mile path in Missouri, Illinois and Indiana, the longest on record. The second worst was the St. Louis tornado of 1896, which killed 255 people. The third worst was the Joplin tornado.



LOSS OF LIFE

Forbes said the most striking thing about the Joplin tornado is that so many people died in this day of advanced communication and warning systems.

“The most terrifying thing about Joplin was the number of fatalities when we have such sophisticated weather and communications technology,” he said. “It was the deadliest since 1947.

“This is what used to happen when there was no radar and when forecasts did not use the word ‘tornado.’ I never thought I would see this kind of tornado event ever again. I did not think I would see it.”

Forbes said Joplin is an example of what happens when “a big one marches itself through an urbanized area with structures not built to withstand those winds. At that point, it becomes a matter of good or bad luck whether you survive.”

After the outbreak in 1974, a number of measures were taken to improve building codes, and detection and warning systems for severe storms. It was during that outbreak that Forbes worked with Fujita to do damage surveys. Forbes said he hopes the outbreak 2011 will spur new measures to enhance public safety.

“I’m hoping it will,” he said. “What happened in 1974 gave a greater urgency to a national network of Doppler radars. This may cause something too. The National Weather Service is planning a series of meetings to talk about improvements to the weather readiness of the nation.”

One such idea, under research in Oklahoma, is to mount less-expensive radar on existing cell towers that “can act as gap-filling radar to cut down on false alarms,” he said.

Other ideas could involve changes in building codes, the construction of shelters, better awareness, better communications and upgraded radar.