Dr. Jeff Masters' WunderBlog

2011: Year of the Tornado

Posted by: Dr. Jeff Masters, 7:25 PM GMT on December 27, 2011

+45

The year 2011 will forever be known as Year of the Tornado in the U.S. A series of violent severe storms swept across the Plains and Southeast U.S., bringing an astonishing six billion-dollar disasters in a three-month period. The epic tornado onslaught killed 552 people and caused $25 billion in damage. Three of the five largest tornado outbreaks on record hit in a six-week period, including the largest and most expensive tornado outbreak in U.S. history--the $10.2 billion dollar Southeast U.S. Super Outbreak, April 25 - 28. Even more stunning was the $9 billion late-May tornado outbreak that brought an EF-5 tornado to Joplin, Missouri. The Joplin tornado did $3 billion in damage and killed 158 people--the largest death toll from a U.S. tornado since 1947, seventh deadliest tornado in U.S. history, and the most expensive tornado in world history. In a year of amazing weather extremes, this year's tornado season ranks as the top U.S. weather story of 2011.

Video 1. Remarkable video of the tornado that hit Tuscaloosa, Alabama on April 27, 2011. Fast forward to minute four to see the worst of the storm.

Figure 1. A truly frightening radar image: multiple hook echoes from at least ten supercell thunderstorms cover Mississippi, Alabama, and Tennessee during the height of the April 27, 2011 Super Outbreak. A multi-hour animation is available here.

A record six EF-5 tornadoes confirmed in 2011
Six top-end EF-5 tornadoes hit the U.S. in 2011, tying this year with 1974 for the greatest number of these most destructive tornadoes. The EF-5 tornadoes of 2011:

1) The April 27, 2011 Neshoba/Kemper/Winston/Noxubee Counties, Mississippi tornado (3 killed, 29 mile path length.)

2) The April 27, 2011 Smithville, Mississippi tornado (22 killed, 15 mile path length.)

3) The April 27, 2011 Hackleburg, Alabama tornado (71 killed, 25 mile path length.)

4) The April 27, 2011 Rainsville/Dekalb County, Alabama tornado (26 killed, 34 mile path length.)

5) The May 22, 2011 Joplin Missouri tornado (158 killed, 14 mile path length.)

6) The May 24, 2011 Binger-El Reno-Peidmont-Guthrie, Oklahoma tornado. (9 killed, 75 mile path length.)

Figure 2. Aerial view of damage from the May 22, 2011 Joplin, Missouri tornado. Image credit: Wikipedia.

Figure 3. EF-5 damage from the April 27, 2011 Neshoba tornado in Mississippi. The tornado was so powerful that it dug out the ground to a depth of two feet over an area 25 - 50 yards wide and several hundred yards long. Image credit: NWS.

A few other remarkable statistics on the tornado season of 2011, compiled from NOAA's official press release, the NOAA Extreme Weather 2011 page, and Wikipedia's excellent tornado pages:

- The tornado death toll of 552 in 2011 ties 1936 as the second deadliest year for tornadoes in U.S. history. Only 1925, with 794 fatalities, was deadlier. In 1936, violent tornadoes hit Tupelo Mississippi (216 killed), and Gainesville, Georgia (203 killed.) During the 1930s, the tornado death rate per million people was 60 - 70 times as great as in the year 2000 (Figure 4), implying that this year's tornadoes may have killed tens of thousands of people if we did not have our modern tornado modern warning system.

Figure 4. Death rate per million people per year in U.S., 1875-2011. Thin line with dots is raw rate, curved thick line is death rate, filtered by 3-point median and 5-point running mean filter, and straight solid lines are least squares fit to filtered death rate for 1875-1925 and 1925-2011. Dashed lines are estimates of 10th and 90th percentile death rates from 1925-2000. The death rate fell from 8 per million to .12 per million between 1940 and 2010. Image credit: A Brief History of Deaths from Tornadoes in the United States, Harold Brooks and Charles Doswell III, and updated by Harold Brooks in 2011.

- April 2011 had the most tornadoes of any month in U.S. history--753. The previous record was 542, set in May 2003. The previous busiest April was in 1974, with 267 tornadoes. The average number of tornadoes for the month of April during the past decade was 161, and the 30-year average for April tornadoes was 135.

- On April 27, 199 confirmed tornadoes touched down. This is the largest 1-day tornado total on record, beating the 148 recorded in 24 hours on April 3 - 4, 1974.

The year 2011 now has three of the top five tornado outbreaks on record (note, though, that reliable records for number of tornadoes only extend back in time to about the early 1990s):

- The April 25 - 28, 2011 Super tornado outbreak, with 343 tornadoes, is now the largest tornado outbreak in U.S. history. The previous record (3 days or less duration) was 148 tornadoes, set during the April 3 - 4, 1974 Super Outbreak.

- The May 22 - 27, 2011 tornado outbreak, with 180 confirmed tornadoes, ranks as the 4th largest 6-day or shorter tornado outbreak on record. A May 2003 6-day outbreak had 289 tornadoes, and a May 2004 6-day outbreak had 229 tornadoes.

- The April 14 - 16, 2011 tornado outbreak, with 177 confirmed tornadoes, ranks as the second largest tornado outbreak of three days or less duration on record, and 5th largest outbreak of six or fewer days duration.

- The May 22, 2011 Joplin, Missouri tornado killed 158 people and injured 1150, making it the deadliest U.S. tornado since 1947, and 7th deadliest in history. The $3 billion estimate of insured damage makes it the most expensive tornado in world history.

- Preliminary damage estimates from Munich Re insurance company put 2011's insured losses due to U.S. thunderstorms and tornadoes at $25 billion, more than double the previous record set in 2010.

- The year 2011 now ranks in 2nd place behind 1973 for greatest number of tornadoes greater than EF-0 strength (EF-1, EF-2, EF-3, EF-4 and EF-5 strength, Figure 5.)

Figure 5. Number of EF-1, EF-2, EF-3, EF-4 and EF-5 tornadoes from 1950 to 2011. The total shown for 2011 is preliminary and uses unofficial numbers through November 17, but 2011 now ranks in 2nd place behind 1973. There is not a decades-long increasing trend in the numbers of tornadoes stronger than EF-0, implying that climate change, as yet, is not having a noticeable impact on U.S. tornadoes. However, statistics of tornado frequency and intensity are highly uncertain. Major changes in the rating process occurred in the mid-1970s (when all tornadoes occurring prior to about 1975 were retrospectively rated), and again in 2001, when scientists began rating tornadoes lower because of engineering concerns and unintended consequences of National Weather Service policy changes. Also, beginning in 2007, NOAA switched from the F-scale to the EF-scale for rating tornado damage, causing additional problems with attempting to assess if tornadoes are changing over time. Data provided by Harold Brooks, NOAA/National Severe Storms Laboratory.

Other posts looking back at the remarkable weather events of 2011
Deadliest weather disaster of 2011: the East African drought
Tropical Storm Lee's flood in Binghamton: was global warming the final straw?
Wettest year on record in Philadelphia; 2011 sets record for wet/dry extremes in U.S.
Hurricane Irene: New York City dodges a potential storm surge mega-disaster

The NWS posted a summary of the records set during the tornado season of 2011 in February 2012.

Jeff Masters

Joplin Tornado Damage (thebige)

Tornado - Pine Apple,AL (EarlBcom)

Tornado just south of Pine Apple, AL on around 5:40pm. This storm was a part of the Alabama tornado outbreak on April 15, 2011. earlb.com VIDEO - See video of tornado at earlb.com

As Is (teach50)

My husband and I were visiting my parents in Birmingham, Alabama. We decided to take a day trip to Tuscaloosa to see the damage from the April 27 tornado. It was a sight that I will never forget. Blocks and blocks of flattened houses and stores. This area has not been touched in 2 months. It was so moving that I started to cry thinking of all these poor people.

Categories: Tornado Extreme Weather

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601. washingtonian115 6:49 PM GMT on December 30, 2011
I am RAH-DAY for the cold next week.Finally some real cold after dealing with these sissy cold temps that have been hanging around since November.Come on old man winter let's GET IT ON!!!.(aaaaand for those of you who are thinking negativly you need to stop :). Member Since: August 14, 2010 Posts: 5 Comments: 10655

602. CosmicEvents 6:57 PM GMT on December 30, 2011
Quoting BtnTx: I totally agree the wx-related info here is the best because of highly informed members who comment and often including great links! I think the weather part has been going downhill for 2-3 years. MOST of the best amateur/pro mets have given up. What's left is a shell of what it was. But worst of all, the Dr., who I respect for his science and his tropical cyclone forecasting, sort of phoned it in this year on the tropical cyclone part. Many posts were 98% re-run with a new paragraph at the top. I always used to count on what the NHC said first, and the Dr. second. This year, I had to look elsewhere. . As for the blog comment part..that's a mess. Been going downhill since the /- system started. We'll see what next year's season brings. . Good health to all. Member Since: August 3, 2005 Posts: 10 Comments: 5099

603. FtMyersgal 7:02 PM GMT on December 30, 2011
Quoting pottery: True. Better for them to delete the mail, and advise the sender. At least that would be the honest way... IMO Member Since: September 16, 2010 Posts: 0 Comments: 995

604. BtnTx 7:02 PM GMT on December 30, 2011
I guess I am a little out of touch as I don't often have much time to come here. Maybe this blog has degraded. I hope Levi32 is still around come hurricane season. I did not realize a weather blog war was going on! Member Since: October 12, 2001 Posts: 20 Comments: 876

605. washingtonian115 7:03 PM GMT on December 30, 2011
Oh lord...are people having flash backs of "The blog was better a few years ago than it is today" syndrome? Member Since: August 14, 2010 Posts: 5 Comments: 10655

606. Neapolitan 7:04 PM GMT on December 30, 2011
Dr. Masters has a new blog entry up. Member Since: November 8, 2009 Posts: 4 Comments: 11157

607. SPLbeater 7:11 PM GMT on December 30, 2011
Quoting washingtonian115: Oh lord...are people having flash backs of "The blog was better a few years ago than it is today" syndrome? since this morning it seems. i went and pulled my punching bag out of the corner and started smackin that thing for awhile, come back and no improvement LOL Member Since: August 4, 2011 Posts: 43 Comments: 3954

609. hydrus 7:26 PM GMT on December 30, 2011
Quoting Patrap: That toll likely to go higher as well hydrus, as the impact zone is a very poor area. There may be hope tho. The warnings were in place well in advance of the storm, and most people heeded there warnings. Member Since: September 27, 2007 Posts: 1 Comments: 14297

610. tulsahurrcane 8:05 PM GMT on December 30, 2011
Quoting pottery: It's an interesting debate, right now. With the Internet making it possible for everyone to have a say in everything, even copyright and private statements are subject to abuse. And there is a huge grey area between what I might consider private, and what you might consider your 'right' to know. I think that we will see "censorship" as we know it (being the assumed right of a person to remain private) coming to an end. I personally cannot think of this as anything but intrusion and noseyness . But with the popularity of "Reality" TV being a good example (our desire to witness the mindless goings-on of complete strangers, and worse, believing it!!!), I think that we are witnessing the end of Individualism and with it the end of Mental Progress. We are evolving into a sort of Group-Brain entity. There is a forum for every thought we have. We can join that forum for reinforcement of our views, or to diss the opposite view. It's a basic requirement of Homo Sapiens to belong to a tribe, party, religion or whatever. It's also a very natural thing for the members of that 'tribe' to prevent outsiders from coming in, especially if they are brandishing new ideas. Nothing has changed really. There will always be people who will question the Status Quo, and these people are often feared and mistrusted because they create doubts in the minds of "comfortable" folk. Your Constitution was penned many years ago. Aspects of it have been changed to take into account the changes within your Society. It is a 'work-in-progress', as it should be. And if it was not so it would have failed. It's a mistake to think that all change is bad. You made some good points there Pottery. Change is inevitable, but I find some of it hard to deal with, as you know. Member Since: August 15, 2010 Posts: 0 Comments: 129

611. CosmicEvents 9:32 PM GMT on December 30, 2011
Quoting blakels: Again, the issue here is not privacy, but the fact that words that you type with your fingers are altered without your knowledge before they reach the intended recipient. And you have no idea what the recipeient actually received. This sets a very disturbing precedent. A bad precedent indeed. That same rule that gives WU the right to edit your private e-mail also gives them the right to edit the public posts you make, potentially changing your point of view 180 degrees. Bad precedent indeed. Better to just remove the e-mail, or dare I say remove the post. Member Since: August 3, 2005 Posts: 10 Comments: 5099

612. hcubed 2:45 AM GMT on December 31, 2011
Quoting Sangria: You are correct. Any member who signed up agreed to the terms and conditions. I believe that "linking" to a commercial weather site is prohibited. I accept that this is the rule; however, if I mention that I saw a posting of value on the bunker site in a WU mail to another WU member, this is not linking for promotional purposes. Yet, my email is changed. Not only is it changed on the recipient's end, it is also changed in my "sent" box, as though I actually typed the "changed" words. This practice, I believe, would be beyond questionable. Also, of note.....the rule regarding linking to commercial sites is not applied to any other websites that I tested, except for .com ( this is the Bunker site I have typed, in case it is changed). I tested the following in my own WU mail account. Within the account it changes the Bunker site to wunderground.com....here is this blog comment, I believe it will change it to just ".com" wunderground.com .com----->this is the Bunker website weather.com accuweather.com thextremeweather.com These were just a few that I tested, but it was enough to determine that this is not a "rule" that is being enforced, but IS an attempt to restrict a member's ability to share information. And, in the much used "community standards", we find this: "...Linking to External Sites Generally, links to non-commercial (that is, personal) weather sites, personal sites/blogs, and especially photographers' site (even commercial) are allowed. If sites are found to contain information or discussion that goes beyond our own rules or is found to be abusive it will be removed..." Member Since: May 18, 2007 Posts: 286 Comments: 1639

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