1974 Super Outbreak

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https://www.weather.gov/iln/19740403_aerial

[Hoosier]

https://www.ustornadoes.com/2013/04/03/looking-back-at-the-april-3-4-1974-super-outbreak/

[chuckster2012]

I saw one of the Ohio ones from about 1-2 miles away. Awesome..

[The_Doctor]

Maybe a dumb question, but is there any chance that there were a lot more tornadoes that occurred on that day than we know of? Since it was back in the 1970s? Especially since 30 violent tornadoes occurred out of 148 total, while the 2011 super outbreak had "just" 15 violent tornadoes but 216 total tornadoes. I imagine part of the gap can be explained by the fact that April 27th featured a lot of early morning tornadoes even before the "main event" got going.

[Hoosier]

5 hours ago, The_Doctor said:

Maybe a dumb question, but is there any chance that there were a lot more tornadoes that occurred on that day than we know of? Since it was back in the 1970s? Especially since 30 violent tornadoes occurred out of 148 total, while the 2011 super outbreak had "just" 15 violent tornadoes but 216 total tornadoes. I imagine part of the gap can be explained by the fact that April 27th featured a lot of early morning tornadoes even before the "main event" got going.

Virtually certain that there were more than 148 tornadoes that day, at least imo, despite the effort that went into mapping that outbreak.  

[andyhb]

Also I get the feeling several of those F4+ tornadoes might be downgraded on the current EF-scale, although Fujita and co. surveyed this thing themselves.

[Wmsptwx]

I agree with andyhb, especially looking at damage pics of a few. Certainly most prolific of all time, but some F4s likely would be 3s today.

[CheeselandSkies]

5 hours ago, andyhb said:

Also I get the feeling several of those F4+ tornadoes might be downgraded on the current EF-scale, although Fujita and co. surveyed this thing themselves.

While certainly featuring an inordinate number of very intense tornadoes, I agree the '74 outbreak was probably not as far ahead of its 2011 cousin in terms of tornado intensity as the official (E)F3-5 counts would indicate. Many of the violent tornadoes in the 2011 event, including several EF4s, did notably more intense damage across a greater portion of their path lengths than all but a few of the official F5s (particularly Brandenburg and Guin) in 1974.

The only thing that in my mind keeps the 2011 event from being unquestionably worse than 1974 is the lack of coverage of violent tornadoes further north into KY/IN/OH. It was much worse for Alabama, however with the morning QLCS spawning a large outbreak in and of itself.

To me, the ultimate outbreak would combine the coverage of the 1974 Super Outbreak (Dixie Alley through OH Valley into southern Lakes) with the concentrated tornadic violence that was visited on the 1st and 3rd of those regions in 2011 and on Palm Sunday 1965, respectively.

[Southern stream]

If we didn't have the rain/clouds in the OH valley on 4/27, IMO it would have been equal in terms of the strong/violent tornadoes of 74. Either way you look at it though, 11 EF4 and 4 EF5s are generational in terms of one outbreak! Was looking into 74 a few weeks ago. The CAPE/Shear space was insane over such a large geographical area and apparently there was convection prior to the supercells just like 4/27, it had laid boundaries, but did not hamper CAPE build-up as it got out in time before the main show. 

[Indystorm]

In 1973 at Indiana Univ. I wrote a Master's thesis on "Tornado Disaster Planning for Public Schools in Indiana," one year prior to this historic outbreak.  After the disaster I met my former academic advisor at a professional meeting and he was aghast.  His daughter was a student at Hanover at the time it was struck with many buildings damaged but was not injured.  He was amazed at my foresight.  I'll never forget his initial reaction upon seeing me. Just glad that some of the recommendations did more than end up on dusty library shelves in the interests of safety. I used the bulk of the research on the 1965 Palm Sunday tornado outbreak to produce the thesis.

[buckeye]

this is insane:

"The 1974 outbreak featured 30 violent tornadoes in less than one day when the national average is only about 7 per year."

 

imagine if this happened in recent times...AOC's green deal would probably have gotten some votes.

[CheeselandSkies]

It just about did in the form of 4/27/11. See my earlier post for my thoughts as to why it was not unquestionably worse than '74.

[hlcater]

4 hours ago, buckeye said:

this is insane:

"The 1974 outbreak featured 30 violent tornadoes in less than one day when the national average is only about 7 per year."

 

imagine if this happened in recent times...AOC's green deal would probably have gotten some votes.

 

Doubt it.

[Stebo]

7 minutes ago, hlcater said:

Doubt it.

Recency bias, I agree with Buckeye.