Hoosier Posted March 28, 2016 Share Posted March 28, 2016 As severe weather aficionados know, Tom Grazulis is the authority on tornadoes prior to the official period of record, as he attempted to catalog every significant tornado going back many years. I've seen some NWS offices make maps of the pre-1950 tornadoes in their respective cwa's, but as far as I know, nobody has broadened it out into a regional effort. So I decided to take the info from Grazulis and make a regional map. However, my map is just the violent F4-F5 tornadoes and NOT all significant tornadoes. Below are the approximate tracks for all the F4-F5 tornadoes from 1880-1949, as rated by Grazulis. I also included fatality numbers for each tornado, located beside each track. There are 167 tornadoes on my map, and these 167 tornadoes produced 2,989 fatalities (actual count may be a bit higher as follow-up reports of fatalities were not always published back in those days). Only about 10 tornadoes did not produce deaths. It's gotten better nowadays with more awareness, advanced warning, etc. but clearly F4-F5 tornadoes still pose a disproportionate threat to life. Some of these tornadoes were likely tornado families, especially the longer tracks. Link to comment Share on other sites More sharing options...
madwx Posted March 29, 2016 Share Posted March 29, 2016 Interesting to note the lack of violent tornadoes in the eastern half of Wisconsin once you get above the southern row of counties. Wonder how much of that is related to the influence of Lake Michigan. Although after 1950 there have been numerous F4-F5 tornadoes in eastern Wisconsin, including the Oakfield F5, Wales F4 and Oshkosh F4. So that contradicts my hypothesis. Link to comment Share on other sites More sharing options...
andyhb Posted March 29, 2016 Share Posted March 29, 2016 I might need to add some of these (across all of the states) to my F4-F5 tornado table that currently spans from 1900-2015. Link to comment Share on other sites More sharing options...
Hoosier Posted March 29, 2016 Author Share Posted March 29, 2016 Interesting to note the lack of violent tornadoes in the eastern half of Wisconsin once you get above the southern row of counties. Wonder how much of that is related to the influence of Lake Michigan. Although after 1950 there have been numerous F4-F5 tornadoes in eastern Wisconsin, including the Oakfield F5, Wales F4 and Oshkosh F4. So that contradicts my hypothesis. Yeah, I don't know if there's any rhyme or reason to the distribution a lot of times. One thing that is true in both the pre and post 1950 eras is the generally sharp dropoff in occurrence once you get east of western Ohio or so, with the exception of a couple rogue events. Link to comment Share on other sites More sharing options...
Hoosier Posted March 29, 2016 Author Share Posted March 29, 2016 I checked 1950-2015 numbers for the same region and there were about 170 violent tornadoes, which is very close to the number from 1880-1949. Not exactly the same number of years but pretty close...each era comes out to about 2.5 per year, give or take. Link to comment Share on other sites More sharing options...
on_wx Posted March 29, 2016 Share Posted March 29, 2016 I can dig up info/tracks for Ontario F4 tornadoes in this time frame Link to comment Share on other sites More sharing options...
cyclone77 Posted March 29, 2016 Share Posted March 29, 2016 Too bad the map didn't start 20 years earlier back in 1860. We could probably add another green track (F5) through eastern Iowa into northwest Illinois with a tornado that killed 141 people. http://www.iawx.net/2009/06/04/historical-wx-the-camanche-tornado-of-1860/ Link to comment Share on other sites More sharing options...
daddylonglegs Posted March 29, 2016 Share Posted March 29, 2016 Nothing around here... This area (knock on wood) seems to really lack the tnads...must be the old local saying that where 3 rivers meet (Mississippi/Black/LaCrosse) tornadoes don't form (i'm sure that has been proven untrue elsewhere...but i guess it works here). Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted March 29, 2016 Share Posted March 29, 2016 That F4 track directly through the Chicago metro would really be a unimaginable event today. Also the multiple tracks over the exact same area in vermillion county (il) is incredible. Link to comment Share on other sites More sharing options...
OHweather Posted March 29, 2016 Share Posted March 29, 2016 I checked 1950-2015 numbers for the same region and there were about 170 violent tornadoes, which is very close to the number from 1880-1949. Not exactly the same number of years but pretty close...each era comes out to about 2.5 per year, give or take.It's rather remarkable that the numbers for each era come out so close, and in my mind helps lend some credence to the pre-1950 numbers for at least violent tornados. Awesome work on the map! Link to comment Share on other sites More sharing options...
Hoosier Posted March 29, 2016 Author Share Posted March 29, 2016 That F4 track directly through the Chicago metro would really be a unimaginable event today. March 28, 1920...may have been a break in that path in Dupage county. The worst damage was just east of the Dupage/Cook county border up through the far northwest side of Chicago. Probably weakened some after that before leaving shore around Wilmette (at least that's my guess based on damage pics I've seen). Link to comment Share on other sites More sharing options...
Hoosier Posted March 29, 2016 Author Share Posted March 29, 2016 It's rather remarkable that the numbers for each era come out so close, and in my mind helps lend some credence to the pre-1950 numbers for at least violent tornados. Awesome work on the map! Thanks. The pre 1950 stuff has some value imo...and at least those ratings were consistently applied by the same person vs. what happened after that (especially for tornadoes from 1950-early 1970s that fell into the massive retroactive rating project). In general I've found Grazulis to lean conservative when in doubt...there are some instances where he mentions "possible F5" but gives it F4, "possible F4" but gives it F3 and so on. Link to comment Share on other sites More sharing options...
on_wx Posted March 29, 2016 Share Posted March 29, 2016 Aside from the Windsor F4 of 1946 that's already on the map, the only other pre-1950 F4 in Ontario struck Stormont, Dundas and Glengarry County east of Ottawa on July 17, 1902. It killed 5 people and injured 12. Brick buildings and homes were 'totally destroyed', trees were snapped at their bases, and barns were reduced to splinters. According to newspaper reports it was described as an angry hornets nest shape. Link to comment Share on other sites More sharing options...
cyclone77 Posted March 30, 2016 Share Posted March 30, 2016 It's rather remarkable that the numbers for each era come out so close, and in my mind helps lend some credence to the pre-1950 numbers for at least violent tornados. Awesome work on the map! Woops, didn't realize Hoosier actually constructed the map. My bad. Feel kind of bad about saying I had wished the map had started back in 1860 lol. I agree with the others in that it's a very nice map. Lots of work there. I'm surprised at how little there is in west-central IL down by Macomb, etc. North-central and northwest IL blew away (no pun intended) that area away during this era, which seems somewhat contradictory to how I visualize trends today. Link to comment Share on other sites More sharing options...
Hoosier Posted March 30, 2016 Author Share Posted March 30, 2016 Woops, didn't realize Hoosier actually constructed the map. My bad. Feel kind of bad about saying I had wished the map had started back in 1860 lol. I agree with the others in that it's a very nice map. Lots of work there. I'm surprised at how little there is in west-central IL down by Macomb, etc. North-central and northwest IL blew away (no pun intended) that area away during this era, which seems somewhat contradictory to how I visualize trends today. No problem man...wasn't offended at all. Actually could've gone back into the 1870s but cut if off at 1880...not sure why lol. That area you mentioned has still been a bit of a dead zone after 1950 in terms of violent tornadoes. Link to comment Share on other sites More sharing options...
RCNYILWX Posted March 30, 2016 Share Posted March 30, 2016 Great work on this Hoosier. That F4 track from March 28, 1920 across Chicago is something else. With the work that's been done recently on our tornado climatology page, a plot like one you created would be a nice addition. Sent from my SM-G935V using Tapatalk Link to comment Share on other sites More sharing options...
Hoosier Posted March 30, 2016 Author Share Posted March 30, 2016 Great work on this Hoosier. That F4 track from March 28, 1920 across Chicago is something else. With the work that's been done recently on our tornado climatology page, a plot like one you created would be a nice addition. Sent from my SM-G935V using Tapatalk Thanks. Was looking at LOT's tornado climo page recently...great job. Link to comment Share on other sites More sharing options...
sokolow Posted April 2, 2016 Share Posted April 2, 2016 Fantastic Hoosier, thanks. This is neat. Thanks. The pre 1950 stuff has some value imo...and at least those ratings were consistently applied by the same person vs. what happened after that (especially for tornadoes from 1950-early 1970s that fell into the massive retroactive rating project). In general I've found Grazulis to lean conservative when in doubt...there are some instances where he mentions "possible F5" but gives it F4, "possible F4" but gives it F3 and so on.Asking out of curiosity does Grazulis discuss what kind of difficulties there were in obtaining contemporary observations reports, & accounts in sparsely populated areas with limited roads Link to comment Share on other sites More sharing options...
sokolow Posted April 2, 2016 Share Posted April 2, 2016 Too bad the map didn't start 20 years earlier back in 1860. We could probably add another green track (F5) through eastern Iowa into northwest Illinois with a tornado that killed 141 people. http://www.iawx.net/2009/06/04/historical-wx-the-camanche-tornado-of-1860/ Thanks, this was cool!OT but as far as historical tornadoes go I enjoyed this read (abs; full view .pdf is free) http://journals.ametsoc.org/doi/abs/10.1175/2010BAMS2874.1 on the August 1521 Tlatelolco tornado Link to comment Share on other sites More sharing options...
Hoosier Posted April 2, 2016 Author Share Posted April 2, 2016 Fantastic Hoosier, thanks. This is neat. Asking out of curiosity does Grazulis discuss what kind of difficulties there were in obtaining contemporary observations reports, & accounts in sparsely populated areas with limited roads He does talk about population playing a role in reporting. Link to comment Share on other sites More sharing options...
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