I've spent quite a bit of time digging into the numbers and quite honestly, what happened last weekend is pretty unbelievable.
First off, here's where things stand right now. Remember that these numbers are preliminary and may change.
The main purpose of this thread is to focus on this subforum as that's where almost all of the tornadoes occurred. In fact, 71 out of 74 tornadoes occurred from Missouri-Kentucky northward (3 EF0/EF1 occurred in TN). The November 10, 2002 tornado outbreak gets brought up quite a bit since it was a significant outbreak, but from a regional perspective, this outbreak has demolished that one.
nov2002c.png 36.02KB 10 downloads
If we broaden out for a moment, we see that the preliminary total from 11/17/2013 has surpassed the total from 11/10/2002, and that outbreak had a much broader geographic reach.
nov2002b.png 45.77KB 10 downloads
If we're really generous and include the tornadoes that occurred late on the 9th and into the early 10th (which technically shouldn't be part of the outbreak as many hours went by until the next tornado), the total does surpass what occurred last weekend, but again, over a much bigger area.
nov2002.png 46.08KB 10 downloads
Back to focusing on this subforum. I'm going to take some time to focus on the two states that bore the brunt of this outbreak, Illinois and Indiana.
The preliminary total of 24 tornadoes in Illinois would tie for 5th place. Here are the most active tornado days on record in Illinois:
I wanted to broaden things out beyond November outbreaks so I looked at other fall months. Here are the single day September/October/November tornado records (or what were the November records) for Illinois:
9/26/1959: 12 … F2 or greater: 9/26/1959: 6
10/24/2001 and 10/26/2010: 5 … F2 or greater: 10/10/1969 and 10/18/2004: 2
11/12/1965: 6 … F2 or greater: 11/12/1965: 5
Those November numbers are not typos. The previous high for tornadoes in a single day was 6 while the previous high for F2 or greater tornadoes was 5. The preliminary numbers for 11/17 are 24 tornadoes with 14 of them EF2+. Pretty astonishing.
Doing the same thing for Indiana, starting with most active tornado days on record...
(4 out of the top 5 days are from the past 10 years...better detection anyone?)
Now, here are the single day September/October/November tornado records (or what were the November records) for Indiana:
9/20/2002: 6 … F2 or greater: 9/20/2002: 4
10/26/2010: 13 … F2 or greater: 10/24/1967: 6
11/22/1992: 15 … F2 or greater: 11/22/1992: 10
The current preliminary numbers for 11/17 (28 tornadoes/13 EF2+) beat the numbers from the 1992 outbreak.
Here's a bunch of factoids regarding this outbreak:
-11/17 is the first November tornado outbreak to produce multiple violent tornadoes in the region let alone the same state
-There had never been an F/EF4 tornado in Illinois in November from 1950-2012 and there were 2 on 11/17. Grazulis indicates no F4s in Illinois going back to 1880.
-There had only been 20 F/EF2 or greater tornadoes in Illinois in November from 1950-2012 and there were 14 on 11/17.
-There had only been 27 F/EF2 or greater tornadoes in Indiana in November from 1950-2012 and there were 13 on 11/17.
Finally, to get a sense of how significant this outbreak was, I wanted to look at other notable tornado days in the subforum. I define this subforum to be approximately the area in red:
map.png 16.45KB 9 downloads
Using Tornado History Project, I was able to put together a list of days that had the most F/EF2 or greater tornadoes in the subforum. Per the map above, this includes all of Wisconsin, Michigan, Illinois, Indiana, Ohio, Kentucky, and small parts of Minnesota, Iowa and Missouri.
Here are the days with the most F/EF2 or greater tornadoes:
4/19-20/1996: 15 (includes IN/KY tornadoes after midnight)
There's all kinds of caveats with rating/assessing damage and one of them is that some long track tornadoes from the past may have really been multiple tornadoes. That being said, that is some pretty fine company. FWIW, the previous single day November record for the subforum was 11 (11/22/1992).
In summary, this was a very impressive event and I believe it's the new benchmark for Fall severe weather outbreaks, especially for the Lakes/Ohio Valley Region on the whole.