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Tornado in Dewey County, South Dakota
27 tornadoes events in the NCEI Storm Events record, 1950 to 2026. Event types counted: Tornado.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. Storm records through 30 Jun 2026.
Dewey County, South Dakota, has 27 tornado events in the NCEI record since 1950, with at least one in 18 different years.
June is the busiest month, with 13 of the recorded events. The last 20 years account for 9 events against 7 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 1.4% of the 1,947 tornado events recorded in South Dakota; its 1.2 per 100 square miles compares with 2.6 statewide.
By rating: 18 at (E)F0, 1 at (E)F1, 4 at (E)F2, 0 at (E)F3, 0 at (E)F4, 0 at (E)F5 and 4 unrated. Tornadoes before 2007 carry the original Fujita rating.
Compared with South Dakota
| Measure | Dewey County | South Dakota | US |
|---|---|---|---|
| Tornado events since 1950 | 27 | 1,947 | 81,281 |
| Per 100 square miles | 1.2 | 2.6 | 2.3 |
| Per 10,000 residents | 51.5 | 21.7 | 2.4 |
| Deaths recorded | 0 | 19 | 6,410 |
| Busiest month | June | June | May |
By year
Seasonality
0Feb
0Mar
0Apr
1May
7Jun
13Jul
3Aug
2Sep
1Oct
0Nov
0Dec
0
Magnitude distribution
Enhanced Fujita scale wind estimates
- EF0/F0
- 65–85 mph (EF0)
- EF1/F1
- 86–110 mph (EF1)
- EF2/F2
- 111–135 mph (EF2)
- EF3/F3
- 136–165 mph (EF3)
- EF4/F4
- 166–200 mph (EF4)
- EF5/F5
- over 200 mph (EF5)
- Unrated
- no rating recorded
Tornado rating as recorded (Fujita scale before February 2007, Enhanced Fujita after).
Recorded events
All 27 events, most recent first. Magnitude is hail size, tornado rating or wind speed as recorded.
| Date | Event type | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|
| 21 Jun 2014 | Tornado | EF0 | — | — | — | — | County |
| 16 Jun 2010 | Tornado | EF2 | — | — | — | — | County |
| 26 Jun 2008 | Tornado | EF0 | — | — | — | — | County |
| 26 Jun 2008 | Tornado | EF0 | — | — | — | — | County |
| 26 Jun 2008 | Tornado | EF0 | — | — | — | — | County |
| 24 May 2008 | Tornado | EF0 | — | — | — | — | County |
| 24 May 2008 | Tornado | EF0 | — | — | — | — | County |
| 24 May 2008 | Tornado | EF0 | — | — | — | — | County |
| 24 May 2008 | Tornado | EF0 | — | — | — | — | County |
| 24 Jun 2006 | Tornado | F0 | — | — | — | — | County |
| 2 Aug 1997 | Tornado | F0 | — | — | — | — | County |
| 24 Jun 1997 | Tornado | F0 | — | — | — | — | County |
| 31 May 1996 | Tornado | F0 | — | — | — | — | County |
| 12 Jul 1995 | Tornado | F0 | — | — | — | — | County |
| 6 Jul 1994 | Tornado | F0 | $50K | — | — | — | County |
| 1 Jun 1990 | Tornado | F0 | — | — | — | — | County |
| 24 Sep 1986 | Tornado | F1 | $25K | — | — | — | County |
| 23 Jul 1985 | Tornado | F0 | — | — | — | — | County |
| 18 May 1977 | Tornado | — | $3K | — | — | — | County |
| 19 Jun 1970 | Tornado | — | — | — | — | — | County |
| 6 Aug 1968 | Tornado | — | — | — | — | — | County |
| 8 May 1965 | Tornado | — | — | — | — | — | County |
| 8 Jun 1964 | Tornado | F0 | — | — | — | — | County |
| 8 Jun 1964 | Tornado | F2 | — | — | — | 1 | County |
| 8 Jun 1964 | Tornado | F0 | $25K | — | — | — | County |
| 19 Apr 1955 | Tornado | F2 | $3K | — | — | — | County |
| 2 Jun 1953 | Tornado | F2 | $25K | — | — | — | County |
Questions and answers
How many tornado events has Dewey County had?
27 events in the NCEI Storm Events record between 1950 and 2026. Reporting of tornadoes became far more complete after 1996, so early decades undercount.
When was the last recorded tornado event in Dewey County?
21 Jun 2014 (Tornado, EF0). Records reach NCEI about 120 days after the month ends.
What was the most damaging tornado event recorded in Dewey County?
The tornado of 6 Jul 1994, with property damage estimated by NCEI at $50K.
How does Dewey County compare with South Dakota for tornado?
1.2 events per 100 square miles against 2.6 statewide; the county holds 27 of the state's 1,947 recorded events.
Provenance
NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026, public domain. County-recorded events plus zone-recorded events whose forecast zone is named for the county (marked "Forecast zone"). Population and area from the US Census Bureau (2021). Built 1 Oct 2026. See the methodology, the Tornado hub and the county page.