In late 2023, American
meteorologist
A meteorologist is a scientist who studies and works in the field of meteorology aiming to understand or predict Earth's atmospheric phenomena including the weather. Those who study meteorological phenomena are meteorologists in research, while th ...
and
tornado
A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, alt ...
expert
Thomas P. Grazulis created the
outbreak intensity score (OIS) as a way to rank
tornado outbreak
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A tornado outbreak is the occurrence of multiple tornadoes spawned by the same synoptic scale weather system. The number of tornadoes required to qualify as an outbreak typically are at least six to ten, with at least two rotational ...
s.
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.
The number of total points determine the rating for the outbreak, which is broken up into seven categories.
List
Super outbreaks
There have been two tornado outbreaks which scored more than 250 points on the OIS, reaching the status of "super outbreak".
Historic outbreaks
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".
Devastating outbreaks
There have been several tornado outbreaks which scored at least 80 points, but less than 120 on the OIS, reaching the status of "devastating outbreak".
Major outbreaks
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".
See also
*
Tornado intensity and damage
Tornado intensity can be measured by ''in situ'' or remote sensing measurements, but since these are impractical for wide-scale use, intensity is usually inferred by proxies, such as damage. The Fujita scale, Enhanced Fujita scale, and the Int ...
*
List of tornadoes and tornado outbreaks
A ''list'' is any set of items in a row. List or lists may also refer to:
People
* List (surname)
Organizations
* List College, an undergraduate division of the Jewish Theological Seminary of America
* SC Germania List, German rugby union ...
**
List of F5 and EF5 tornadoes
This is a list of tornadoes which have been officially or unofficially labeled as F5, EF5, T10-T11, IF5, or an equivalent rating, the highest possible ratings on the various tornado intensity scales. These scales – the Fujita scale, the Enhanc ...
**
List of F4 and EF4 tornadoes
This is a list of tornadoes which have been officially or unofficially labeled as F4, EF4, IF4, or an equivalent rating. These scales – the Fujita scale, the Enhanced Fujita scale, the International Fujita scale, and the TORRO tornado in ...
***
List of F4 and EF4 tornadoes (2010–2019)
***
List of F4 and EF4 tornadoes (2020–present)
This is a list of tornadoes which have been officially or unofficially labeled as F4, EF4, IF4, or an equivalent rating during the 2020s decade. These scales – the Fujita scale, the Enhanced Fujita scale, the International Fujita scale, and th ...
*
List of tornadoes striking downtown areas
This article is a list of tornadoes that have impacted the central business district (downtown or city center) of a large city (that is, one having at least 50,000 people, not counting suburbs or outlying communities, at the time of the storm).
I ...
*
Tornado myths
Tornado myths are incorrect beliefs about tornadoes, which can be attributed to many factors, including stories and news reports told by people unfamiliar with tornadoes, sensationalism by news media, and the presentation of incorrect information ...
References
{{reflist
Tornado-related lists
Lists of events lists