US killer tornadoes: some key figures

[Pierre Ducray]

[Tornadoes]
Number of US tornadoes per year: 1,225.1 (1991-2020 average).

Lowest number*: 886 in 2014.
Highest number*: 1,813 in 2004.

[Killer tornadoes]
Number of US killer tornadoes per year: 20 (1991-2020 average).

Lowest number*: 9 in 2018 and 2009.
Highest number*: 59 in 2011.

[Killer tornadoes vs. tornadoes]
Percentage of US killer tornadoes per year: 1.6% (1991-2020 average).

[Killer tornadoes]
Number of fatalities in the US per year: 69 (1991-2020 average).

Lowest number*: 10 in 2018.
Highest number*: 553 in 2011.

*1991-2020 lowest and highest numbers

Sources: National Centers for Environmental Information/Storm Prediction Center.

 

[Mike Smith]

Thanks for posting, Pierre.

 

[Pierre Ducray]

US killer tornadoes: some key figures (Part 2)
Fatalities by circumstance/location.

✓ 1991-2020 average and 1991-2020 highest numbers.

✓ In bold the 5 years with the highest total number of fatalities (2011 [553 fatalities, including the May 22 Joplin tornado]; 1998 [130]; 2008 [127]; 1999 [94] and 2007 [81]).


"MANUFACTURED/MOBILE HOME" category:
40.8%
Highest numbers of fatalities in this "Manufactured/mobile home" category: 112 in 2011, 64 in 1998, 56 in 2008, 49 in 2007, 48 in 2012.

"HOUSE" category:
33.2%
Highest numbers of fatalities in this "House" category: 229 in 2011, 46 in 1998, 43 in 2008, 39 in 1999.

["Manufactured/mobile home" category + "House" category= 74%]

"PERMANENT BUILDING/STRUCTURE" category :
9.5%
Highest numbers of fatalities in this "Permanent building/structure" category: 92 in 2011, 21 in 1994 (including 20 in a church in Alabama on Palm Sunday, March 27).

["Manufactured/mobile home" category + "House" category + "Permanent building/structure" category= 83.5%]

"VEHICLE" category:
8.2%
Highest numbers of fatalities in this "Vehicle" category: 34 in 2011, 18 in 2008, 16 in 1998.

"UNKNOWN" category:
4.4%
Highest number of fatalities in this "Unknown" category: 79 in 2011.

"OUTDOORS" category:
3.9%
Highest numbers of fatalities in this "Outdoors" category: 14 in 1991, 7 in 2011, 1999 and 1997.

SOURCES: National Weather Service, National Centers for Environmental Information, Storm Prediction Center.

 

[Pierre Ducray]

US killer tornadoes: some key figures (Part 3)

The 20 US states with the highest total number of fatalities (1991-2020 period).

ALABAMA: 413 (19.9% of the total number of fatalities in the US for that period) including 238 on April 27, 2011 (tornado outbreak)

MISSOURI: 248 (12%) including 158 on May 22, 2011 [Alabama+ Missouri= 31.9% of the total number of fatalities in the US for that period]

TENNESSEE: 205 (9.9%) [Alabama+ Missouri+ Tennessee= 41.8%]

GEORGIA: 144 (6.9%) [Alabama+Missouri+Tennessee+Georgia= 48.7%]

OKLAHOMA: 140 (6.8%) [OK+above states=55.5%]

MISSISSIPPI: 135 (6.5%) [MS+above states=62%]

ARKANSAS: 122 (5.9%) [AR+above states=67.9%]

TEXAS: 105 (5.1%) [TX+above states=73%]

FLORIDA: 92 (4.4%) [FL+above states=77.4%]

KANSAS: 57 (2.8%) [KS+above states=80.2%]

INDIANA: 52 (2.5%) [IN+above states=82.7%]

NORTH CAROLINA : 50 (2.4%) [NC+above states=85.1%]

KENTUCKY: 45 (2.2%) [KY+above states=87.3%]

ILLINOIS: 43 (2.1%) [IL+above states=89.4%]

LOUISIANA: 42 (2%) [LA+above states=91.4%]

IOWA: 24 (1.2%) [IA+above states=92.6%]

OHIO: 23 (1.1%) [OH+above states=93.7%]

SOUTH CAROLINA: 21 (1%) [SC+above states=94.7%]

MINNESOTA: 17 (0.8%) [MN+above states=95.5%]

VIRGINIA: 17 (0.8%) [VA+above states=96.3%]

SOURCES: National Weather Service, National Centers for Environmental Information, Storm Prediction Center.

 

[Pierre Ducray]

US killer tornadoes: some key figures (Part 4)

US killer tornadoes by intensity


US killer F5/EF5 tornadoes (1991-2020 period): 412 fatalities ( 19.9% of the US total number of fatalities for that period).

✓ Including the Joplin (Missouri) tornado (158 fatalities) on 05/22/2011 and the Moore (Oklahoma) tornado (24 fatalities) on 05/20/2013.

✓ No US killer F5/EF5 tornado (for that 1991-2020 period) before April 8 and after June 16.

✓ All US killer F5/EF5 tornadoes (for that 1991-2020 period) in 8 states: Alabama, Iowa, Kansas, Oklahoma, Minnesota, Mississippi, Missouri, Texas.


US killer F4/EF4 tornadoes (1991-2020 period): 569 fatalities (27.5%).


US killer F3/EF3 tornadoes (1991-2020 period): 666 fatalities (32.15%).

✓ Including the El Reno (Oklahoma) tornado (8 fatalities) on 05/31/2013 (11 days after the Moore EF5 tornado).


US killer F2/EF2 tornadoes (1991-2020 period): 294 fatalities (14.2%).


US killer F1/EF1 tornadoes (1991-2020 period): 104 fatalities (5%).


US killer F0/EF0 tornadoes (1991-2020 period): 26 fatalities (1.25%).


[Sources: National Weather Service, National Centers for Environmental Information, Storm Prediction Center]

 

[Elaine Spencer]

Interesting stats! Note that the average number of annual tornado deaths is 69; if you subtract 4/27 (316 (?) fatalities) and Joplin (158 fatalties) from the 2011 total, you're left with 79 deaths from all the other tornadoes and outbreaks that year (and there were many). Those two outliers have a big impact on the overall stats.