Dewey County, South Dakota severe weather history spans 516 recorded events between 1953 and 2025. The dominant hazard is hail, accounting for 51.0% of all recorded events. It ranks #820 nationally and #26 in South Dakota.
516
Recorded events
0
Direct deaths
1
Direct injuries
$1.0M
Property damage
The record
What the Dewey County, South Dakota severe weather history record shows
Across the archive, Dewey County, South Dakota severe weather history averages 7.2 recorded events a year. The busiest stretch on record is the 2010s, with 162 events logged in that decade alone. Roughly 43 events fall before 1990 and 473 from 1990 onward — a gap that reflects the expansion of NOAA reporting practice as much as the weather itself.
The costliest is flood, with $774K in reported property damage. In total, 7 distinct hazard types appear in this county archive, each listed with its own dated record below.
By hazard type
Every hazard type recorded in Dewey County
| Hazard | Events | Deaths | Damage | Max | Span |
|---|---|---|---|---|---|
| Hail | 263 | 0 | $0 | 4 | 1957–2025 |
| Thunderstorm Wind | 192 | 0 | $5K | 123 | 1959–2025 |
| Tornado | 27 | 0 | $130K | F2 | 1953–2014 |
| Flood | 17 | 0 | $774K | 0 | 2007–2025 |
| Flash Flood | 14 | 0 | $110K | 0 | 1997–2017 |
| Funnel Cloud | 2 | 0 | $0 | 0 | 2010–2021 |
| Lightning | 1 | 0 | $0 | 0 | 2005–2005 |
Decade by decade
Dewey County, South Dakota severe weather history by decade
Reporting practice changed over time — early decades are undercounted, not calmer.
Tornado tracks
Paths crossing this county
32 mapped tornado paths intersect this county: 31 touched down inside it and 1 crossed in from a neighbouring county. This comes from path geometry, not county-tagged reports.
| Date | Scale | Deaths | Injuries | Path length | Origin |
|---|---|---|---|---|---|
| 2010-06-16 | EF2 | 0 | 0 | 0.4 mi | Touched down here |
| 1964-06-08 | EF2 | 0 | 1 | 3.8 mi | Touched down here |
| 1955-04-19 | EF2 | 0 | 0 | 0.1 mi | Touched down here |
| 1953-06-02 | EF2 | 0 | 0 | 5.9 mi | Touched down here |
| 1986-09-24 | EF1 | 0 | 0 | 0.3 mi | Touched down here |
| 1977-05-18 | EF1 | 0 | 0 | 0.1 mi | Touched down here |
| 1977-07-10 | EF1 | 0 | 0 | 16.0 mi | Crossed in |
| 2014-06-21 | EF0 | 0 | 0 | 0.3 mi | Touched down here |
| 2008-05-24 | EF0 | 0 | 0 | 0.1 mi | Touched down here |
| 2008-06-26 | EF0 | 0 | 0 | 0.3 mi | Touched down here |
Significant events
Deadliest events on record in Dewey County
| Date | Type | Location | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Jun 8, 1964 | Tornado | 0 | 1 | $0 |
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Very heavy rains of 4 to 7 inches caused flash flooding in several areas along Highway 212 from west of Lantry to Eagle Butte. Several homes and businesses along with most roads in Eagle Butte were flooded with quite a bit of damage received.
Runoff from very heavy rains caused the Moreau River to rise above flood stage on June 5th. The river crested at 25.4 feet on June 8th before falling back below flood stage on June 10th. Flood stage on the Moreau River is 21 feet.
Heavy rain caused flash flooding on the Moreau River with the bridge on Route 14 being overtopped. The bridge had to be closed west of Green Grass. A basement was also flooded three miles east of Green Grass along with several roads in the area.
Context
Risk, population and federal disasters
Relatively Low
FEMA NRI risk rating
5,205
Population (ACS)
$70K
Median home value
17
Federal declarations
| Declared | Incident | Title | Type |
|---|---|---|---|
| Apr 5, 2020 | Biological | COVID-19 PANDEMIC | DR |
| Apr 5, 2020 | Biological | COVID-19 PANDEMIC | DR |
| Mar 13, 2020 | Biological | COVID-19 | EM |
| Jun 7, 2019 | Flood | SEVERE WINTER STORM, SNOWSTORM, AND FLOODING | DR |
| Feb 1, 2017 | Severe Storm | SEVERE WINTER STORM | DR |
| Jul 28, 2014 | Flood | SEVERE STORMS, TORNADOES, AND FLOODING | DR |
Quick answers
Frequently asked
How many severe weather events have been recorded in Dewey County, South Dakota?
516 events are on record between 1953 and 2025, causing 0 direct deaths and $1.0M in property damage.
What is the most common severe weather hazard in Dewey County?
Hail, with 263 recorded events — 51.0% of everything in the archive for this county.
How many tornadoes have crossed Dewey County?
32 mapped tornado paths intersect the county boundary; 31 of them touched down inside it. This is derived from path geometry, not county-tagged reports.
How many federal disaster declarations cover Dewey County?
17 federal disaster declarations from FEMA include Dewey County, each tied to a specific incident period.
How risky is Dewey County compared with the rest of the country?
FEMA's National Risk Index rates Dewey County as relatively low risk, placing it in the 79 percentile of its state for expected annual loss.
Where does the Dewey County, South Dakota severe weather history data come from?
Every figure is drawn from United States federal public-domain records: NOAA/NCEI Storm Events for the event archive, NOAA SPC SVRGIS for mapped tornado paths, FEMA for disaster declarations and risk ratings, and the U.S. Census for population context. Dates are shown in UTC and recent entries may still be revised by NOAA.
Nearby
Neighbouring counties
- Deuel County 264
- Douglas County 227
- Day County 456
- Edmunds County 547
- Davison County 467
- Fall River County 677
Cite this page
“Dewey County, South Dakota.” Severe Weather History. severeweatherhistory.com/county/south-dakota/dewey-county/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.