While many climate alarmists still try to tell us that global warming will increase tornadoes, we are in the middle of a tornado drought, and well below normal. Normally we’d see 1221 tornadoes in the USA, so far for 2013, only 716 have been reported.
![ptorngraph[1]](http://wattsupwiththat.files.wordpress.com/2013/08/ptorngraph1.png?resize=610%2C397)
The map of the USA shows the distribution:
So far, we are about 200 tornadoes below this time last year, and last year was also a low event year.
![torngraph-big[3]](http://wattsupwiththat.files.wordpress.com/2013/08/torngraph-big3.png?resize=640%2C416)
When looking historically at where we are, we find that 2013 has slipped below the historical minimum, setting a new record for the ~60 years in the tornado database.
![torgraph-big[3]](http://wattsupwiththat.files.wordpress.com/2013/08/torgraph-big3.png?resize=640%2C396)
What’s more, we are well past the time of peak tornado activity, which typically occurs in spring, when we have the most collisions between warm and cold air masses over the USA. While we could certainly see a rebound, it is statistically unlikely.
![tor_month[1]](http://wattsupwiththat.files.wordpress.com/2013/08/tor_month1.png?resize=640%2C339)
Sources: NOAA Storm Prediction Center
http://www.spc.noaa.gov/climo/online/monthly/newm.html
http://www.spc.noaa.gov/wcm/
There must be a way for the warmists to spin this into “it’s worse than we expected…”
Don’t worry – NOAA will be sending observers to the western US to make sure dust devils make it into the tornado count…
http://en.wikipedia.org/wiki/Dust_devil
Looks like an extreme lack of extreme weather.
They are hiding at the bottom of the ocean….
…and when you least expect it
BAM
Aren’t tornadoes vital renewers of the environment?
Climate change – it’s worse than we thought!!
There may well be fewer tornadoes, But, But… The tornadoes are getting bigger and stronger. /src
The warmer’s will deny this and stick their head up their hockey sticks.
Warmists should rejoice in extreme weather rather than trying to scare children about such things at bedtime. Extreme weather is healthy for the earth. If the trend is showing more moderation in weather and climate, that is not good. After studying the Milankovitch cycles, and where the earth currently stands regarding them… nope, not good at all… moderate=bad; extreme=good.
Any deviation from average is due to Catastrophic Anthropogenic Global Warming.
Here is the spin: Too much CO2 it makes the air heavier with less tornados but they are more destructive. Ha
The chart on frequency by month adds up to 256 per year, so it isn’t a percentage, and it isn’t near the number reported for annual totals. The source doesn’t leap out at me from the links. What are the numbers reporting?
Just so you know…you’ve hit Drudge Report…the masses will be flooding!
It’s the calm before the storm. By 2060, half of all the humans in developing countries will have been killed by tornadoes. Not only that, but 100% of the crops on the planet will be destroyed by them, and everyone will starve. You deniers disgust me.
Oh god Where is Al Gore! He needs to explain this right now! Nah this wont matter. The raging eco nuts will never look at reality. They will always dodge real questions and facts.
“It’s worse that we… ummm…. umm… er… never mind”
This will never appear in liberal media.
There is a good reason for this and the 30 years is just on time. The globe goes through phases of warming and cooling on small normal cycle just like change of seasons and then every so often, drastic changes where Palm Trees grow in Northern Canada or Ice is in Florida all winter with snow but none of that will happen in the next few hundred years so we are simply in the 30 average cycle.
I predicted global warming back in the 70s when news was Ice Age since winters were so cold and we got global warming and I predicted global cooling to start once the PDO went negative again because of the Sun which controls 97% of climate on earth. We started new cold phase March of this year and the Arctic Ice buildup in March was growing outside of 1979 levels on the Eastern side as expected however; new ice and snow melts faster in summer so it will take a good 3-5 years to see that grow outside of those levels but the bottom line is we had the 2nd coldest spring on record and we will start to see growing seasons become shorter, winters on average longer and colder with more La Nina than El Nino activity. Get your coats out because it is going to get cold and there will be tornado activity based on climatology from the 30 year last cold phase instead of last 30 years. Hurricane tracks are also changing back to 1950-1980 patterns so expect winters to be much like those in the 50s-70s before we switch to global warming again.
Humans cause City heat Island effect, pollution and nothing more. It’s too long to write and explain other than 33 thousand scientists agree with my statement.
Well, yeah, but now they come with sharks…
[snip . . I assume you were indulging in sarcasm, in which case you need to indicate that with a /sarc tag for those of our visitors for whom English is not their first language and they may take you seriously. In the event you were being serious please repost. thanks . . mod]
Damn……that “global warming”…….
We need that NWO “carbon tax” to save the tornadoes.
The walarmists Just can’t seem to wrap their teensy little brains around the fact that we are now in a cooling phase. Even NASA’s own numbers show that, but you wouldn’t know it based on their own press releases. They parse and spin their own numbers in a vain attempt to pander to the Glo-BULL warming alarmists, but to no avail. I think this quote attributed to one of the greatest minds ever, Albert Einstein, says it best: “The difference between genius and stupidity is that genius has its limits.”
So much for that “climate change” theory….
We may have a lack of tornados, but what about Sharknado! Global warming has to be responsible for that!!
What, Al Gore Was Wrong??????
@climatetruther – I never argue against ones religious beliefs.
That’s terrible news. See, that’s climate change. They should be staying the same. We’re doomed.
This made Drudge, with thanks to Marc Morano.
In other news, sharknado sightings are down…
What’s even more impressive than getting a “record” low with “record” levels of C02 in the atmosphere is doing it now when we have bigger populations and better technology to observe a greater percentage of such extremely local events as tornadoes than we used to.
Must be all that global warm…..er, climate cha…..er……., Al Gore will think of something.
Here’s the surprising news. We have record low tornadoes and record low July temps. Want to know that cause? Right, global warming. You see, no matter the effect, global warming is the cause because it is the models which are correct, not the actual measurable facts on the ground.
AGW sounds more and more like religion every day.
…..tornados up its global warming….tornados down its global warming….!
Yeah, I saw this on the evening news on all of the MSM stations… said no one ever.
It’s the 9th highest tornado count since 2005. 🙂
There may not be many, but each is because of global warming. There would have been none without global warming. /
Of course there is “climate change”. We just have no impact on it. I mean, the Earth was just recently almost completely covered in ice and warmed from that without an SUV in sight. How does the Left explain that?
It’s because Algore has not been out speaking much lately. When he gets back on the lecture circuit, he will produce enough hot air to bring this tornado deficit right back into balance.
The 4th chart (Percentile Ranks) are on the Reference Pages: Climatic Phenomena: Extreme Weather, but it is hard to find. You have to know to look for it. The 3rd chart, which compares an anual view, series by recent year, should also be added to the page.
May I suggest a separate category in the “Reference Pages: Updated Daily”
It would serve as a index page to all charts with volitile content. That way, the Tornado Trend chart updated daily will not be below the Hurricane charts which are updated yearly.
Looks like NOAA is already padding the numbers. In Colo. they show 2 west of the Continental Divide. Tornado’s in this area rarely touch down and are never more than F1. Dust devils may be a better term.
Roy Spencer had the perfect antidote for Al Gore’s fairytales.
So we are shattering records of mild climate. Something gone wrong…..more taxes and less liberty can solve this issue.
Dust Devils suck also. I got hit by one on a clear hot day that was about 200 feet across. 1st there was a slight lifting action followed by my ears popping like when lifting off the ground in an airplane. Then the lifting thing again followed by a massive headache. What can be done about this churning of the atmosphere?
I do love the outdoors. Also got ran over by an F2 here in Nebraska. No big deal, I was inside a concrete bunker designed to throw bluerock out the front and it easily protected us from the debris floating around outside.
I wish people would better prepare for the events that happen where they live rather than try to stop it from happening. You can’t stop nature from happening. Deal with it.
I do like the fact that more false prophecies are getting ousted.
The climate warming snake oil salesmen are doing everything they can to show that global warming is affecting the planet but, the actual facts dispute their claims. They claim to persent video eveidence that the north pole isce cap is melting faster than normal only to have to pull back after it was released that their camera has floated several hundred miles out to sea so that it was capturing oppen sea wwater and ton polar ice. In addition, the Antartic ice cap is actually grwoing larger at a fast rate.
Global warming threatens tornadoes! Tornadoes have now been placed on the endangered species list just below polar bears. I can’t believe the inhumanity of it all! We need cap and trade now before it’s too late! Our grandchildren may never see another tornado!
It’s global warming I tell you and it’s going to get much worse. Can you imagine the chaos if we had a season without hurricanes? We need to quickly form an expensive task force to figure out if we can restart the tornadoes before more events like this spread. I would be willing to accept the paltry sum of 10 million a year over the next 10 years to head up a team that can complete an impact study of how goldfish are the root cause of the current global crisis.
@Alabama Mike “Children just aren’t going to know what a tornado is…”
Perhaps I am missing something but it seems to me that the data showing average tornadoes per month should add up to the average annual tornadoes for the period covered. At 265 it is not even in the same universe. Can someone explain what I am misunderstanding?
@Michael Markowitz
Where are you getting the 265 number from?
Maybe Wile E. Coyote ran out of Acme Instant Tornado pellets!
Bob says:
August 19, 2013 at 9:50 am
“…their camera has floated several hundred miles out to sea so that it was capturing oppen sea wwater and ton polar ice…”
Multiple typos notwithstanding, let’s stay with the facts here: The camera was already “out to sea”- the Arctic Sea. And it didn’t photograph “open sea water.” It was a melt pond on top of the ice, which subsequently re-froze.
To make a respectable argument- or criticism- it’s important to have the facts straight.
Michael Markowitz: The climatology graph is only for Northern Indiana. Not sure why it’s posted here. http://www.crh.noaa.gov/iwx/?n=svrwxclimo
“2013 is a record low year for U.S. tornadoes”
And 2014 could be a record high.
Let me spin this towards AGWing. They must be tired so I will step in to help.
“Tornadoes and hurricanes are Mother Earth’s heat vents. Thank goodness we have them. However global warming is shutting them down to the extent that we will soon be tornado and hurricane free by 2050. We must reduce CO2 so that hurricanes and tornadoes can return to their previous natural climatological state.” [this next part was in the email to each other] And, if we use the word “weirding” we can connect it to CO2.
There. All ready for the press conference.
I’m genuinely perplexed by the reaction of most warministas steadfastly refusing to accept GOOD NEWS like this. It’s real information based on real data that they can confirm to their little hearts’ desire but they always get angry about it.
It just goes to prove Rush Limbaugh’s assertion that these people are invested in the general idea that humans are “hurting the planet”. THAT is the only explanation that fits them. A normal person would hear good news and be relieved to think maybe things aren’t all that bad after all. But nooooooo, not for these perpetually outraged warministas and Gore sycophants, the slightest reduction of any threat to the planet, (or polar bears or species X or Tuvalu, etc.), is apparently an enormous increase of a threat to … their egos.
I guess I can’t blame them too much, the longer they hang on to this hoax the further they’ll “fall” having to either admit they were duped for so many years or worse – guilty of of knowing they were wrong and intentionally perpetrating the hoax for personal benefit.
So now they even count trash can molester, dust devils ( the ones on the map in Ca.)
Desperation is setting in.
Probably just a faulty breaker at HAARP.
I came here for the comments. I’m leaving quite satisfied.
KevinM says: “And 2014 could be a record high.”
Unlikely unless we get extensive snow pack in the upper tier states and Canada. Warm moist air from the Gulf of Mexico is going to push northward almost every Spring making COLD dry air the predetermining factor for tornadoes – not global warming.
In fact, a reduction of storm intensity makes meteorological sense in a warmer world because the polar regions generally warm faster than the tropics thus creating a condition of LESS of a difference in air mass energies which is what drives weather.
Pathway says:August 19, 2013 at 9:40 am
Looks like NOAA is already padding the numbers. In Colo. they show 2 west of the Continental Divide. Tornado’s in this area rarely touch down and are never more than F1. Dust devils may be a better term.
At first glance I would agree with you, having been a storm spotter on the front range, now retired to the more mild-weathered western slope. I wondered where their map depicted those outriders, and making an overlay, it appears to be SE of Gunnison around Hwy 50 and North of Alamosa around Hwy 287. Both of these are in the San Luis Valley, wide-open plains. I would think the elevation would minimize the likelihood of tornado formation, which may be apparent in the low numbers there.
Obama will solve this problem in his 3RD Term!
Mike M says: August 19, 2013 at 10:22 am
I’m genuinely perplexed by the reaction of most warministas steadfastly refusing to accept GOOD NEWS like this.
_________________________________
They don’t want good news. They are Jeremiahs**, who only want bad news, because only bad news will prove them correct. Thus bad news is good news, and the worse the better.
.
** Jeremiah was the mad Judaic priest from the Book of Jeremiah, who wanted god to destroy the exiled Jews, because that would prove that his god was good and looking after the exiled Jews – or something like that. The theology of Jeremiah was as baffling as the theology of the Greens, which is why we should never submit to the insanity of a theocracy.
I see more tornadoes as it got colder….and less as it got warmer
….we’re in trouble 🙂
I just sold all of my worldly possessions to save the POLAR BEARS. Phewy… looks like the polar bear saving people are doing a great job cloud dusting like in the 70’s. The data now supports it. Great job polar bear activists.
Bill says:
August 19, 2013 at 10:12 am
Thanks, Bill, that answers my question as well.
Anthony: The 265 is the total of the monthly values in the last chart (monthly frequency of tornadoes 1980-2000)
It’s that pesky global normal, again.
It looks like the hurricane season is off to a slow start this year.
http://www.weatherstreet.com/hurricane/2010/hurricane-climatology.gif
THANK YOU SO MUCH FOR POSTING THIS!
We linked to it “Climate Change Update” on Common Cents…
http://www.commoncts.blogspot.com
Anthony Watts says:
August 19, 2013 at 10:04 am
@Michael Markowitz
Where are you getting the 265 number from?
Anthony the last graph with the red bars totals 265 tornadoes. So I think he saying since the average for all months is 265 then the average for any year should be 265 but that is not what is indicated.
Cut down on CO2 emissions….Start skip breathing. You really don’t need all of that O2 you are consuming. Do you?
Actually, this is not true. The science is settled so we are having record drought, hurricanes, and tornadoes. And, the fact that it is getting colder – Atlanta had a high of 73 just a few days ago – only reinforces that global warming is a fact. The hotter it gets the colder it seems. The only thing to fix these horrific weather anomolies is through massive carbon taxes. Don’t worry about the temperatures getting colder after we pay the carbon taxes. We can pay a reverse carbon tax to cause the temperatures to increase and stabalize. I’m so glad we have such smart people in charge.
Such trended statistics are almost meaningless. For example, taking Storm Prediction Center’s own database, for the month of May, there were an actual reported number of 251 tornadoes in 2013, versus 121 actual tornadoes reported for May of 2012 (more than double in 2013), and 326 tornadoes in the high peak year of 2011, followed by 304 tornadoes in 2010, and 250 tornadoes in 2009. Also, the month of May 2013 had 41 tornado-related deaths, versus 0 in the same month of May in the previous year of 2012.
Trended statistics, de-based from seasonal fluctuations, are for practical purposes somewhat useless numbers. 2013 has also been a record cold spring in many states in the U.S., and may be more indicative of a ‘delayed spring,’ meaning there could be additional tornadoes in August and September. 2013 is not even over, so how can an article claim that 2013 is a record low until December 31st of 2013? This article should be fact checked.
The only point that may be somewhat realistic, may be a trended factor of climate change, but other factors should be considered such as regional temperature means etc, A conclusion based on three quarters of tornado statistics, before the last quarter of 2013, is premature. More likely 2013 would indicate a shift in regional distribution of data, and such information won’t be known until December, at the end of the 2013 season,
Nice to see the charts, however.
Facts mean nothing to the climate change crowd. What I find amusing is the same people who howl and wail about evil corporations are completely hoodwinked by evil do-gooders who exploit a love of nature for profit…
Calm before the storm?
Climate change, yet another violation of our rights. The gov’t constantly violates our rights.
They violate the 1st Amendment by caging protesters and banning books like “America Deceived II”.
They violate the 4th and 5th Amendment by allowing TSA to grope you.
They violate the entire Constitution by starting undeclared wars.
Impeach Obama.
Last link of “America Deceived II” before it is completely banned:
http://www.amazon.com/America-Deceived-II-Possession-interrogation/dp/1450257437
As my Sierra Club Niece would say, “There has to be fewer tornadoes before there are more tornadoes.”
Don’t all the climate scientists know that the global warming/ climate change pseudo-research and activism has made their field of study junk science on the level of phrenology, no one will believe anything they say ever again.
@FerdinandAkin says:
August 19, 2013 at 8:08 am
But what is “average”? Taken over 4.5 billion years?
But Obama told me that Global Warming was causing ALL these storms!!!
All of the deniers that global warming is a fictitious UN retribution scheme have constantly told us we would have more tornadoes and hurricanes. If we have less tornadoes and hurricanes, they’ll argue that global warming causes both. Liberalism is a mental illness.
JimS says:
Warmists should rejoice in extreme weather rather than trying to scare children about such things at bedtime. Extreme weather is healthy for the earth. If the trend is showing more moderation in weather and climate, that is not good. After studying the Milankovitch cycles, and where the earth currently stands regarding them… nope, not good at all… moderate=bad; extreme=good.
JimS – please elaborate. Why is moderate weather bad when considering Milankovitch cycles?
Drudge screenshot for the record: http://postimg.org/image/nrxnf815v/
I wish a scientist would investigate why global warming is so much worse during the day than at night.
Here’s how it could be spun…
According to thermodynamics, the ability to extract work does not depend on temperature but on temperature gradient. In particular, tornadoes occur when warm, moist Gulf air meets cool, dry Arctic or Pacific air. If the northern regions are warming, then the temperature difference between these air masses may be lessening, reducing the energy available for tornado creation.
Course the fact that the continental air mass has been cooler than typical this year might argue against the above.
http://www.courierpress.com/news/2013/jun/16/modern-technology-lessens-threat-from-tornadoes/
The Great Tri-State Tornado was actually on March 18, 1925, though the paper made a mistake with March 19 stated. As chief meteorologist on WEHT, Evansville Indiana from 1982-1993, I did reports on the anniversary of that event. I went to some of the hardest hit towns, including Griffin IN that was completely destroyed and interviewed elderly folks who could recall the event like it was yesterday. Incredible stories.
There are numerous links with loads of supporting stats that make this stand out as the “worst” tornado in recorded history. If recorded history went back a million years, surely there were many more similar tornadoes(without people and buildings to destroy).
You’ll find this particular comment from the Encyclopedia Britannica very amusing when viewed from the perspective of todays alarmist world, where the objective is quite different:
“The tornado materialized about 1:00 pm local time in Ellington, Mo. It caught the town’s residents by surprise, as the weather forecast had been normal. (To prevent panic among the public, tornado forecasting was not practiced at the time, and even the word “tornado” had been banned from U.S. weather forecasts since the late 19th century.) ”
http://www.britannica.com/EBchecked/topic/1472896/Tri-State-Tornado-of-1925
2 days later, these were the headlines of the Chicago Herald Examiner.
http://www.historybyzim.com/2013/07/tri-state-tornado/
Good book on it:
http://books.google.com/books/about/The_Tri_State_Tornado.html?id=zXwhIUY9qlYC
Back to the graphs. The 2008 and 2011 years are obviously exceptional.
If temperature trends and correlations are done without the years where El Nino cause spikes why not the same for tornado numbers?
I’ll have to look at earlier data, but it seems the tornado peaks in 2008 and 2011 follow the El Nino that developed in late 2007 and 2010 and brought extra moisture (and rainfall) to the USA west coast.
Excluding the 2008 and 2011 years the average is much lower and the number for 2013 is not exceptional.
N.B. 2013 is still below average and so does not support any claim of increasing extreme weather events.
I do like this information being posted. However,…
A) I’m well aware that these are NOAA charts/graphs, but just how the heck do they “Inflation Adjust” tornadoes? Or are they referring to the damage?
B) Also, I’m not following the charts very well to understand how 60 years of recorded history is being shown. I’m not clearly seeing anything prior to 2005. (Maybe it’s just too late at night.)
C) Finally, I urge GREAT caution here. WE, at least, are referring to “recorded history” a vast step away from “ever” and “in history,” (no “recorded”) the terms “warmistas” use so readily. But, the historical record on this is short (about half that of thermometer records, and only a couple decades longer than the satellite record for hurricanes and other scientific observations as I recall), and we have had substantial changes in the detection technology, so the old records do not have the same potential as today’s to pick up tornadoes that are not seen in a farmer’s field. Yes, of course that means we may be seeing an even GREATER “tornado drought” than these charts suggest, but it’s still something that deserves a footnote.
And, do I dare say these are weather-related phenomena? They are merely one more indicator of a host of weather (and climatic) variables that continue to be rather incompletely (poorly?) understood as a system that includes feedback loops, etc.
@ Ratt:
Have you asked your Sierra Clubber if it’s fewer before more, or more before fewer. Once she ponders that, you might also ask if it’s possible there could be natural variability — what some call “cycles” — of fewer, more, fewer, more, flat, more, fewer, flat,…
🙂
Sure it was a record low, but weren’t they all Mann-made global warming tornadoes????
It is not over until the fat lady sings; however, this is got to be the beginning of the end.
Least number of tornadoes in 60 years.
Highest coverage of sea ice in the Antarctic in recorded history, multiple months. Antarctic sea is has been high for all months of the year. On track to set a record for maximum extent.
http://nsidc.org/data/seaice_index/images/daily_images/S_stddev_timeseries.png
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.antarctic.png
Arctic sea ice extent and likely thickness is recovering.
http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png
http://ocean.dmi.dk/arctic/meant80n.uk.php
What we need now is record low tropical storm and hurricane formation to complete the set.
The finishing on the cake will be record cold winters and negative global temperature anomalies.
Brilliant news for proponents of AGW – now we can badge the next average year as a 50% increase since 2013. Just think of the headlines !
Since it hasn’t been working for 17 years, doesn’t this possibly support a relationship with warming and tornados. Could the lack of tornados be due to stable Global Average Temperature (GAT)?
My guess would be that changes in GAT may correlate with storms. Storms due to increasing temps would remain essentially the same (global warming is really reduced cooling, not increased warming), but the muted fall in temps may reduce storms.
Mike Maguire says:
August 19, 2013 at 4:59 pm
Thanks Mike. I often point to the great Tri-State tornado of 1925 when climate “scientists” and their followers make wild assertions about modern tornadoes being the the “worst ever” due to global warming.
When there is a tornado, and lives are disrupted, the first people to swing into action are the companies (such as Walmart or Lowe’s) whose shipping capacity is efficient and flexible, and whose inventories are able to respond. Growers and millers also move quickly to provide rice to people through schools and churches. Medical and building supplies are also provided after disaster through our powerful fossil fuel based infrastructure.
Then a politician flies in, gets his picture taken, and declares a national emergency.
The greenhouse gas paradigm is yet another abuse of science by government, and these abuses by scientists have a lethal history during the 1900’s, including Lysenkoism and eugenics/population control. There is nothing wrong with co2 from power generation and transportation, methane from dairy cows, and nitrous oxide from rice and wheat.
Here’s a concept totally foreign to the alarmists, it’s called E-QUA-LIBR-IUM. The earth has always cycled between extremes. The alarmists deny this because to do so is to admit how impotent we humans really are in all things climate change. The climate changes not because of us, but despite us. For a group that is allegedly all about nature, they shoor is ignerent of it.
Looks like a possible record low year for hurricanes also. None this year in the entire Atlantic Basin(through August).
……well there you go….global warming has caused a record low year for hurricanes……see how it works?
Wait for it: the Alarmists’ next mantra will have to be hyped anxiety about the radically abnormal moderation of the weather.
……I think that I am having a problem with the term “alarmist”. These people are calculating socialist who believe that there is never too much government control over our lives and that the greatest threat is too much individual liberties…….they don’t give a tinker’s damn about the climate…!
I found an old text book (in my pile of old books) containing a tornado frequency histogram for the period 1916-1960, similar to the graph depicted above “Tornado Frequency by Month 1980-2010”. Here’s the comparison:
-Period- : JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1980-2010: 1 2 12 23 42 71 46 21 9 32 6 0
1916-1960: 5 8 21 37 53 43 22 14 9 12 13 5
Difference -4 -6 -9 -14 -11 28 24 7 0 20 -7 -5
Are the current observation methods (eg storm chasing) introducing a BIAS that increases the tornado count during the warmer months and decreases the count during the cooler months?
Historical data source: “The Earth Sciences” Arthur N Strahler (reprint 1965) Page 286. Title caption for the figure 15.20 was “Frequency of tornadoes in the U.S. by months of the year for the period 1916-1960 (US Dept of Commerce, Weather Bureau)”. Title caption for the graph was “Average Number of Tornadoes Reported”