![]() | Parts of this article (those related to pre-1970 outbreaks) need to be updated.(March 2024) |
In late 2023, American meteorologist and tornado expert Thomas P. Grazulis created the outbreak intensity score (OIS) as a way to rank tornado outbreaks. [1] [2] For the score, only significant tornadoes are counted: F2/EF2 tornadoes receive 2 points each, F3/EF3 tornadoes receive 5 points each, F4/EF4 tornadoes receive 10 points each, and F5/EF5 tornadoes receive 15 points each. [1] The number of total points determine the rating for the outbreak, which is broken up into seven categories. [1]
Type of outbreak | Weak | Minor | Significant | Major | Devastating | Historic | Super |
---|---|---|---|---|---|---|---|
Number of points |
2–6 | 7–10 | 11–29 | 30–79 | 80–119 | 120–249 | 250+ |
There have been two tornado outbreaks which scored more than 250 points on the OIS, reaching the status of "super outbreak". [1]
Outbreak | OIS score | # of (E)F2s | # of (E)F3s | # of (E)F4s | # of (E)F5s | Total tornadoes | Deaths | Injuries | References |
---|---|---|---|---|---|---|---|---|---|
1974 Super Outbreak | 578 | 34 | 35 | 23 | 7 | 148 | 319 | 5,454 | [1] [3] [4] [5] [6] [7] |
2011 Super Outbreak | 378 | 49 | 22 | 11 | 4 | 360 | 324 | 2,892 | [1] [8] [9] [10] |
There have been 24 tornado outbreaks which scored at least 120 points, but less than 249 on the OIS, reaching the status of "historic outbreak". [1]
There have been several tornado outbreaks which scored at least 80 points, but 119 or less on the OIS, reaching the status of "devastating outbreak". [1]
There have been several tornado outbreaks which scored at least 30 points, but 79 or less on the OIS, reaching the status of "major outbreak". [1]
4/26/2024 (NE and IA) had score of 54 (with 12 EF2 and 6 EF3). The next day, 4/27/2024 (mostly OK), had a score of 33 (with 4 EF2, 3 EF3, and 1 EF4.
![]() | Parts of this article (those related to pre-1970 outbreaks) need to be updated.(March 2024) |
In late 2023, American meteorologist and tornado expert Thomas P. Grazulis created the outbreak intensity score (OIS) as a way to rank tornado outbreaks. [1] [2] For the score, only significant tornadoes are counted: F2/EF2 tornadoes receive 2 points each, F3/EF3 tornadoes receive 5 points each, F4/EF4 tornadoes receive 10 points each, and F5/EF5 tornadoes receive 15 points each. [1] The number of total points determine the rating for the outbreak, which is broken up into seven categories. [1]
Type of outbreak | Weak | Minor | Significant | Major | Devastating | Historic | Super |
---|---|---|---|---|---|---|---|
Number of points |
2–6 | 7–10 | 11–29 | 30–79 | 80–119 | 120–249 | 250+ |
There have been two tornado outbreaks which scored more than 250 points on the OIS, reaching the status of "super outbreak". [1]
Outbreak | OIS score | # of (E)F2s | # of (E)F3s | # of (E)F4s | # of (E)F5s | Total tornadoes | Deaths | Injuries | References |
---|---|---|---|---|---|---|---|---|---|
1974 Super Outbreak | 578 | 34 | 35 | 23 | 7 | 148 | 319 | 5,454 | [1] [3] [4] [5] [6] [7] |
2011 Super Outbreak | 378 | 49 | 22 | 11 | 4 | 360 | 324 | 2,892 | [1] [8] [9] [10] |
There have been 24 tornado outbreaks which scored at least 120 points, but less than 249 on the OIS, reaching the status of "historic outbreak". [1]
There have been several tornado outbreaks which scored at least 80 points, but 119 or less on the OIS, reaching the status of "devastating outbreak". [1]
There have been several tornado outbreaks which scored at least 30 points, but 79 or less on the OIS, reaching the status of "major outbreak". [1]
4/26/2024 (NE and IA) had score of 54 (with 12 EF2 and 6 EF3). The next day, 4/27/2024 (mostly OK), had a score of 33 (with 4 EF2, 3 EF3, and 1 EF4.