Climate Change: Tornado myth update
Austin, June 10, 2014 — A popular global warming myth persists saying that “extreme weather” tornadoes are increasing in numbers and intensity. The myth is fueled by news media hype. NOAA’s Storm Event Database disagrees.
The 2014 tornado season is on track to be the weakest on record, according to Dr. Harold Brooks, a long-time senior research analyst at the National Severe Storms Laboratory in Norman, Oklahoma. According to Brooks, this is the 3rd exceptionally weak year in a row.
NOAA records show, as of June 3rd, there have been 35 tornado fatalities in 2014. That compares to 55 in 2013, 70 in 2012 and a whopping 553 in 2011 by June 3rd in those years.
My best guess is that this is the slowest start since 1915, and maybe even 1900
-Dr. Harold Brooks, National Severe Storms Laboratory, 4/22/2014
This year is not just unusual, according to Dr. Brooks, it’s unprecedented. Through May 22nd the fewest number of U.S. tornadoes on record have been recorded.
From Aug. 7, 2013, through April 13, 2014, the Norman, Oklahoma NWS office set a new record for its longest tornado-warning-free stretch, at 316 days. The previous record was 293 days, set in 1991.
Just the facts
Returning to “extreme weather”, tallies of all major F3/F4/F5 and F4/F5 only tornadoes since 1950 show that intense tornadoes have decreased, not increased as the news media would have us believe.
The last bastion of hope for global warming theorists believing that “extreme weather” tornadoes are increasing, rides on the shoulders of the biggest, bad-boy tornado of them all, the frightening F5!
In the movie “Twister”, storm chaser Helen Hunt is the only researcher who’d ever seen an F5. It killed her father when she was a child; sucked him right out of their storm cellar while he valiantly struggling to hold the doors closed. That childhood tragedy drove her to become a tormented tornado hunter who risked her life seeking a way to increase tornado warning times by just a few minutes.
An F5 is the most terrifying tornado of all.
The F5/EF5 tornado record
NOAA lists deadly F5/EF5 tornadoes two ways. One way is a simple list of individual tornadoes. The other way is by tornado events from the storm events database. The difference is a tornado event occurs in only one county. If a tornado crosses county or state lines then it is entered as multiple tornado events, one for each crossing.
Combined, these two listings provide a more accurate assessment of the numbers and intensity of F5 tornadoes over time.
NOAA’s complete record of F5/EF5 tornadoes (blue) and associated tornado events (orange) since 1950 is shown.
The number of tornado events above the number of individual tornadoes gauges the total energy release of the F5 tornadoes involved. The higher the number above, the stronger and more long-lasting the F5 tornadoes involved.
The above graph shows many more tornado events than tornadoes before 1975 compared to after. The trend line (linear regression) that accounts for the relative strength of tornadoes shows a 70 percent decrease since 1950, and there were zero F5s the first three years!
Some have suggested that 63 years isn’t long enough to establish a meaningful trend. They correctly suggest that a longer record with larger numbers of F5s would be more accurate. The pre-1950 work of Thomas Grazulis, documented in the July 1993 text “Significant Tornadoes 1680-1991: A Chronology and Analysis of Events” is cited as a source of additional data.
Additions or updates to the record are unlikely, according to Dr. Brooks. Brooks calls pre-1953 tornado records “sketchy”. Pre-1953 data is less reliable because the SELS program, precursor to the NOAA’s Storm Prediction Center, wasn’t started until 1952.
Brooks suggests that even NOAA’s records are unreliable. He says, “F2-F5 are overrated pre-75, F3-F5 probably underrated 2000-2007”.
According to Brooks, that means the official record of F5 tornadoes shows a steeper decline than it should because of inaccuracies in data collection.
Bottom line, though, no matter how you slice and dice the numbers, deadly “extreme weather” F5 tornadoes have not increased since 1950. If anything, they have decreased.
More about “extreme weather” tornadoes
There are other less direct ways to determine if severe tornadoes are increasing or not.
Fatalities caused by tornadoes are decreasing. That should not surprise anyone.
Weather forecasting, building construction and tornado warning systems are much improved. People have more time to seek shelter. You’d expect deaths to decrease whether tornadoes are becoming more intense or not. We are simply better prepared for them.
This graph shows that property damage caused by tornadoes before 1980 was much higher than after 1980. Costs are levelized using three different methods so that an apples-to-apples comparisons can be made between the years.
A notable exception is the super outbreak of 2011 with very high property damage. However, since then 2012, 2013 and now 2014 are exceptionally weak tornado years with low property damages reported.
The graph comes from a scientific paper titled, “Normalized tornado damage in the United States: 1950–2011” published by Kevin M. Simmons, et. al, in the journal Environmental Hazards, 12/5/2012.
Again, part of the decrease in property damage over time is explained by better warning systems and more tornado-resistant building construction. Forewarned is forearmed.
NOAA’s yearly report of strong to violent tornadoes, which includes all F3/F4/F5 tornadoes, shows that damaging tornadoes have decreased since 1953. Remove the weaker F3 tornadoes from the tally and the results are still the same.
The last glimmer of hope for global warming proponents claiming that “extreme weather” tornadoes are increasing in numbers and intensity rested with the biggest of the big tornadoes, F5. But F5s show a 70 percent decrease since 1950, though the numbers aren’t solid according to Dr. Brooks, tornado researcher at the severe storms lab in Norman, Oklahoma.
Truth is, with only 138 tornado F5 events in the entire NOAA database, a trend line has low statistical value given the wide scatter in F5 yearly tallies.
Even combined with decreases in both fatalities and property damage over time, the numbers do not conclusively prove that “extreme weather” tornadoes are decreasing.
But what it does prove is that “extreme weather” tornadoes are not increasing! The tornado myth, hyped by the media and pushed by global warming theorists, is just that – a myth. It’s a myth that refuses to die.
Update 6/14/2014: More tornado count data added to F5/EF5 counts above that further discredits the myth, commonly believed, that “extreme weather” tornadoes are increasing in numbers and intensity.