SPC Tornado Outbreak Browser

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Dec 21, 2006
90
57
11
Sugar Grove
weather.cod.edu
Wanted to bring this amazing new tool from the SPC to your attention. This is essentially the largest collection of information about tornado outbreaks in a single location. What a great way to cure that SDS!

http://www.spc.noaa.gov/exper/outbreaks/

Huge kudos to Chris Broyles (SPC) and many others who helped make this project a reality. I was able to help contribute by generating all environmental maps prior to '79 using NNRP and 20CR data.
 

chrisbray

EF4
Apr 24, 2012
471
125
11
Bourbonnais, Illinois
It's interesting, but I am having some trouble figuring out how to work the page in some areas because the quantity of information is overwhelming. For example, It shows me long track/violent tornados for North Carolina in the middle section of the page, but I can't tell why it only shows NC or how to change it to an other state.
 
Aug 9, 2012
374
665
21
Galesburg, IL
www.facebook.com
Wow what a awesome tool. I have one question though. It appears as though some of the events are missing tornadoes? May 13, 1995 for example, a high risk day here in Illinois, there were 2 F4 tornadoes (one near Raritan/Roseville and the other near Ipava), it only shows the Ipava storm tornadoes? I realize this was 21 years ago, however this isn't the only source I've seen that leaves these tornadoes out. I'm curious as to why this is, if anyone has insight into this, I'd greatly appreciate it. Especially considering this event is one that is of great interest to me, probably one of the few that sparked my interest in weather. c16444bd81c6b46a13ee173c47d44045.gif


Here is the NCDC article on the missing F4 in this database: https://www.ncdc.noaa.gov/stormevents/eventdetails.jsp?id=10320748

There was also another significant F2 that came after that across Southern Knox County in which I don't see shown.
 
Jun 28, 2007
304
126
11
Machesney Park, IL
Well done, the extensive parameter data alone makes it a fantastic resource for events and the inclusion of radar and satellite (where applicable) is simply superb. I assume the tool will be updated to incorporate future events but will the data for >=1 expand to events prior to 1979 or is that part of the timeline complete?
 
Last edited:

Tim Paitz

EF2
Apr 27, 2015
190
57
11
St. Louis, Missouri
Wow. I want to thank whoever created this page! I do, have the same question as Chris: how do you change it to a different state as it only shows north Carolina?
 
Mar 3, 2012
272
37
11
Wow what a awesome tool. I have one question though. It appears as though some of the events are missing tornadoes? May 13, 1995 for example, a high risk day here in Illinois, there were 2 F4 tornadoes (one near Raritan/Roseville and the other near Ipava), it only shows the Ipava storm tornadoes? I realize this was 21 years ago, however this isn't the only source I've seen that leaves these tornadoes out. I'm curious as to why this is, if anyone has insight into this, I'd greatly appreciate it. Especially considering this event is one that is of great interest to me, probably one of the few that sparked my interest in weather.

Here is the NCDC article on the missing F4 in this database: https://www.ncdc.noaa.gov/stormevents/eventdetails.jsp?id=10320748

There was also another significant F2 that came after that across Southern Knox County in which I don't see shown.
The layout is kind of confusing at first, but near the top of the page there are three navigation bars: "History," "Meteorology" and "Timescale." Timescale allows you to change the time period displayed, so to see the tracks for every tornado in a given event, you want to click "All." Alternatively, if you mouse over "Tornado Tracks" you can choose to display tornado tracks in either 3-hour or 6-hour intervals, and you can then change the time under Timescale by clicking whatever time you want or using the < and > arrows.

There's also a tutorial under About -> Webpage Tutorial, but I haven't watched it so I'm not sure how helpful it'd be.
 
Mar 3, 2012
272
37
11
Wow. I want to thank whoever created this page! I do, have the same question as Chris: how do you change it to a different state as it only shows north Carolina?
I may be wrong, but I don't think you can change it. It appears to be just a bit of random information they've included, not sure why. Same with the tornado photo slideshow below it.
 

chrisbroyles

Enthusiast
May 19, 2009
9
12
1
Wow what a awesome tool. I have one question though. It appears as though some of the events are missing tornadoes? May 13, 1995 for example, a high risk day here in Illinois, there were 2 F4 tornadoes (one near Raritan/Roseville and the other near Ipava), it only shows the Ipava storm tornadoes? I realize this was 21 years ago, however this isn't the only source I've seen that leaves these tornadoes out. I'm curious as to why this is, if anyone has insight into this, I'd greatly appreciate it. Especially considering this event is one that is of great interest to me, probably one of the few that sparked my interest in weather. View attachment 11622


Here is the NCDC article on the missing F4 in this database: https://www.ncdc.noaa.gov/stormevents/eventdetails.jsp?id=10320748

There was also another significant F2 that came after that across Southern Knox County in which I don't see shown.
Ethan, I'm not sure why the Raritan/Roseville F4 tornado and southern Knox County F2 tornado are left out of the SPC tornado track database (1950 to Current). I will look into this. If these are mistakes, then we will make the corrections in our database. If there is some other reason, I'll try to get back to you. Thanks for the heads up on the missing tornadoes.
 
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chrisbroyles

Enthusiast
May 19, 2009
9
12
1
Well done, the extensive parameter data alone makes it a fantastic resource for events and the inclusion of radar and satellite (where applicable) is simply superb. I assume the tool will be updated to incorporate future events but will the data for >=1 expand to events prior to 1979 or is that part of the timeline complete?
Michael, we will be adding the previous year's F4 cases once the official tornado tracks become available each spring. The processing of cases is difficult because of the extensive amount of data and large number of images that are created for each case. However, we will work on updating the cases as weather permits. Thank you for your kind comments.
 

chrisbroyles

Enthusiast
May 19, 2009
9
12
1
It's interesting, but I am having some trouble figuring out how to work the page in some areas because the quantity of information is overwhelming. For example, It shows me long track/violent tornados for North Carolina in the middle section of the page, but I can't tell why it only shows NC or how to change it to an other state.
Chris, the window that shows the longtrack violent tornadoes for North Carolina is just another place for us to display interesting case data. This window is static. We will change the display occasionally with some other graphic once we find something cool.

I understand your feeling of being overwhelmed by the amount of data. I would recommend viewing the tutorial when you get a chance. The tutorial will help you become familiar with how to navigate through the webpage more effectively.
 

chrisbroyles

Enthusiast
May 19, 2009
9
12
1
The layout is kind of confusing at first, but near the top of the page there are three navigation bars: "History," "Meteorology" and "Timescale." Timescale allows you to change the time period displayed, so to see the tracks for every tornado in a given event, you want to click "All." Alternatively, if you mouse over "Tornado Tracks" you can choose to display tornado tracks in either 3-hour or 6-hour intervals, and you can then change the time under Timescale by clicking whatever time you want or using the < and > arrows.

There's also a tutorial under About -> Webpage Tutorial, but I haven't watched it so I'm not sure how helpful it'd be.
Shawn, you're right. The webpage is not intuitive at first. As a person becomes more familiar with how to navigate around, the webpage can become a powerful way to compare tornado events in a very short amount of time. We wanted to make everything available in one place and to reduce the amount of navigation time as much as possible in order to maximize data retention for the user.

As you mentioned, there is a webpage tutorial. It is just under 15 minutes long and I show how to use all the different aspects of the webpage. Viewing the tutorial should be well worth it and make the webpage much easier to use.
 
Mar 3, 2012
272
37
11
Shawn, you're right. The webpage is not intuitive at first. As a person becomes more familiar with how to navigate around, the webpage can become a powerful way to compare tornado events in a very short amount of time. We wanted to make everything available in one place and to reduce the amount of navigation time as much as possible in order to maximize data retention for the user.

As you mentioned, there is a webpage tutorial. It is just under 15 minutes long and I show how to use all the different aspects of the webpage. Viewing the tutorial should be well worth it and make the webpage much easier to use.
It certainly is an incredible resource once you get the hang of it. I think it just overwhelms people at first because of the sheer amount of information. Huge thanks to you and to everyone else who put this together, I'm sure I'll be getting a ton of use out of it. And thanks for including links to my blog as well!
 

chrisbroyles

Enthusiast
May 19, 2009
9
12
1
Wow what a awesome tool. I have one question though. It appears as though some of the events are missing tornadoes? May 13, 1995 for example, a high risk day here in Illinois, there were 2 F4 tornadoes (one near Raritan/Roseville and the other near Ipava), it only shows the Ipava storm tornadoes? I realize this was 21 years ago, however this isn't the only source I've seen that leaves these tornadoes out. I'm curious as to why this is, if anyone has insight into this, I'd greatly appreciate it. Especially considering this event is one that is of great interest to me, probably one of the few that sparked my interest in weather. View attachment 11622


Here is the NCDC article on the missing F4 in this database: https://www.ncdc.noaa.gov/stormevents/eventdetails.jsp?id=10320748

There was also another significant F2 that came after that across Southern Knox County in which I don't see shown.
The F2 in southern Knox County, Illinois shows up on the webpage at the 21Z time for May 13, 1995. The other tornadoes occur at the 00Z time for May 14, 1995. So the F2 in Knox county is on the webpage. We are looking at the Raritan F4 tornado which is not in the SPC database. We should be adding that one after doing some more research. Thanks for bringing this to our attention. It may be awhile before I can update the webpage for this tornado.
 
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chrisbroyles

Enthusiast
May 19, 2009
9
12
1
Wow what a awesome tool. I have one question though. It appears as though some of the events are missing tornadoes? May 13, 1995 for example, a high risk day here in Illinois, there were 2 F4 tornadoes (one near Raritan/Roseville and the other near Ipava), it only shows the Ipava storm tornadoes? I realize this was 21 years ago, however this isn't the only source I've seen that leaves these tornadoes out. I'm curious as to why this is, if anyone has insight into this, I'd greatly appreciate it. Especially considering this event is one that is of great interest to me, probably one of the few that sparked my interest in weather. View attachment 11622


Here is the NCDC article on the missing F4 in this database: https://www.ncdc.noaa.gov/stormevents/eventdetails.jsp?id=10320748

There was also another significant F2 that came after that across Southern Knox County in which I don't see shown.
As was mentioned before, the Knox County F2 is already in the database. Added the Raritan F4 tornado into the SPC database yesterday. A script will be rerun in a couple of weeks and the correction will be made official. I have not had a chance to update the Violent Tornado Webpage for the Raritan F4 tornado but hope to get it done within the next couple of months.
 

chrisbroyles

Enthusiast
May 19, 2009
9
12
1
Wow what a awesome tool. I have one question though. It appears as though some of the events are missing tornadoes? May 13, 1995 for example, a high risk day here in Illinois, there were 2 F4 tornadoes (one near Raritan/Roseville and the other near Ipava), it only shows the Ipava storm tornadoes? I realize this was 21 years ago, however this isn't the only source I've seen that leaves these tornadoes out. I'm curious as to why this is, if anyone has insight into this, I'd greatly appreciate it. Especially considering this event is one that is of great interest to me, probably one of the few that sparked my interest in weather. View attachment 11622


Here is the NCDC article on the missing F4 in this database: https://www.ncdc.noaa.gov/stormevents/eventdetails.jsp?id=10320748

There was also another significant F2 that came after that across Southern Knox County in which I don't see shown.

The Raritan, Illinois F4 tornado on May 13, 1995 has been added to the Violent Tornado Webpage and to the SPC database as well. The Knox County tornado from the same day was already on the Violent Tornado Webpage and in the SPC database. Thanks for bringing these tornadoes to our attention.
 
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Jeff Duda

Resident meteorological expert
Staff member
Supporter
Oct 7, 2008
3,298
2,033
21
Broomfield, CO
www.meteor.iastate.edu
Is this website no longer being updated? The last event that was added was Pilger in 2014.
Half joking, but have there been any events worth adding since then? We haven't had many violent class tornadoes since 2014. What, a couple of isolated EF4s...(some of which occurred in March 2020, which I wouldn't expect to have been added yet anyway).
 

Mark Blue

Owner
Staff member
Feb 19, 2007
3,081
628
21
Colorado
Just a quick internet search defines a tornado outbreak as having 6 - 10 tornadoes from the same synoptic scale system. I didn’t chase Chapman so am not that familiar with the event. I see it was a long track tornado but I’m not sure if it meets the definition of an outbreak per se.
 

Lou Ruh

EF2
May 17, 2007
188
36
11
SE PA
Just a quick internet search defines a tornado outbreak as having 6 - 10 tornadoes from the same synoptic scale system. I didn’t chase Chapman so am not that familiar with the event. I see it was a long track tornado but I’m not sure if it meets the definition of an outbreak per se.
The SPC tool seems to not use that definition. It has 2 columns to choose from ... >= 4 Violent Tornadoes in 3 days ... >=1 Violent Tornado in 1 day ... so, it seems to qualify for inclusion (it was rated an EF4). Not to mention that there were a total of 4 tornadoes that day from that storm and a total of 11 in KS (based on filtered reports at SPC), a day after the Dodge City tornado-fest (arguably the same synoptic scale system).
 

Mark Blue

Owner
Staff member
Feb 19, 2007
3,081
628
21
Colorado
I just emailed Mr. Broyles at the SPC for clarification. Hopefully I’ll hear back from him or he’ll post an update here if he has time.
 

chrisbroyles

Enthusiast
May 19, 2009
9
12
1
Thanks for the questions. On the Violent Tornado Outbreak webpage, there are two columns at the right. One column displays all major violent tornado outbreaks in the U.S. To be a major violent tornado outbreak, the case had to have at least four F4-5s (EF4-5s) within a 72 hour period (12Z to 12Z). The other column is for more localized violent tornado outbreaks in the U.S. The more localized cases had between one and three F4-5s (EF4-5s) in a 24 hour period (12Z to 12Z). While most of the cases are true tornado outbreaks, a few may not be considered outbreaks by many people's standards if the total number of tornadoes is too small. The definition of outbreak ranges widely depending upon who you talk to. I've seen the word "tornado outbreak" refer to cases with a minimum total as little as six tornadoes or as many as 50 tornadoes. I ranked the major outbreaks with at least four violent tornadoes using an equation that considers tornado number, sigtor number and violent tornado number for each case. You can display the major tornado outbreaks in ranked order by using the menu above labeled "Options".

The Pilger, Nebraska case is the last case because the data collection process is very tedious. It takes an incredible amount of work to process each case. Sometimes it can take a week or two just to process one case. And to update the webpage would be a major undertaking that would probably require at least 2 months to complete. Programming languages can change over time making image creation of the required specifications even more difficult. Although there are many new cases that qualify, I just have not had the time to process the new cases. There are literally over a half million images that are stored online. The amount of space taken for the webpage is about 35 gigabytes. So making the database larger is problematic. Finding the time to add new cases is difficult. Right now I am involved in a major radar project looking at tornadogenesis in over 200 violent tornadic supercells. So I just have not had the time to update the violent tornado webpage. But I am glad that people are using it.

If you have any other questions, please don't hesitate to ask.

Chris