Tornadoes of 1918

1. F040 to 72 mph

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. F173 to 112 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. F2113 to 157 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. F3158 to 206 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. F4207 to 260 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. F5261 to 318 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   Grazulis gave no rating: the surviving account records a tornado without enough about the damage to rate it. Almost all of these are before 1880.

1. F5, E Denison to Adaza, IAMay 21, 19184 killed
2. F4 Tyler tornado, MinnesotaAugust 21, 191836 killed
3. F4, Codell, KSMay 20, 19189 killed
4. F4, Boone, IAMay 21, 19189 killed
5. F4, SW Elkport, IA to Baraboo, WIMay 21, 19188 killed
6. F4, Calmar, IAMay 9, 19187 killed
7. F4, NE Bloomfield, NE to Gayville, SDMay 18, 19184 killed

1. F4 Tyler tornado, MinnesotaAugust 21, 191836 killed, 225 injured
2. F3, S Dothan/Webb, ALJanuary 11, 191810 killed, 120 injured
3. F4, Codell, KSMay 20, 19189 killed, 65 injured
4. F4, Boone, IAMay 21, 19189 killed, 70 injured
5. F4, SW Elkport, IA to Baraboo, WIMay 21, 19188 killed, 100 injured
6. F4, Calmar, IAMay 9, 19187 killed, 15 injured
7. F3, E Boynton/N Green City/N Greencastle, MOJune 24, 19187 killed, 10 injured
8. F4, NE Bloomfield, NE to Gayville, SDMay 18, 19184 killed, 15 injured
9. F5, E Denison to Adaza, IAMay 21, 19184 killed, 30 injured
10. F3, Mineola/S Florence, MOApril 2, 19183 killed, 9 injured

Significant tornadoes only

Grazulis listed tornadoes rated F2 or stronger, and weaker ones that killed somebody. Most tornadoes are weaker than F2, so the list holds a fraction of the tornadoes that happened.

The early years are thin

A tornado is on record only where somebody saw it and wrote it down. The count rises through the 1800s with settlement and newspapers, not with the weather.

Rated from accounts

Grazulis rated each tornado decades later from newspaper reports, Weather Bureau records and local histories, not from a damage survey.

The tracks are reconstructed

Tornado Archive drew each path through the places Grazulis names, most often as a straight line from the first to the last. A track can miss a town it hit, and a tornado with one named place is a point. The counties are today’s.

A separate record

SPC’s database, from 1950, counts every confirmed tornado of any strength. The two are kept apart on every page and never added together.

Every year before 19501950, the first year of SPC's databaseThe tornado profiles

Ratings are Grazulis's, read from written accounts of the damage; the rating scale is above. About the record before 1950 says what it holds and what it leaves out.

Thomas P. Grazulis, Significant Tornadoes 1680-1991 and Significant Tornadoes 1880-1989, as digitized by Tornado Archive (Maas and others, 2024). Public domain. Counties assigned by this site from today’s NWS county lines.