Tornadoes and Flash Flood in South Dakota, May 31, 2026

Name: Tornadoes and Flash Flood in South Dakota, May 31, 2026
Start: 2026-05-31T15:35
End: 2026-05-31T21:09
Location: South Dakota

May 31, 2026 · NWS FSD · 24 events in 8 counties and zones

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 24

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS FSD wrote it up.

A trough lifted through the western High Plains as a weak convergence boundary drifted eastward into southeast South Dakota during the late afternoon. Near the boundary, a diurnally destabilized air mass focused convective development in a fairly weak shear environment across the lower James River Valley. Thunderstorms largely produced large hail up to ping-pong ball size during periods of stronger updrafts within the storm clusters. Shear concentrated in lower levels and storm interactions combined to produce several brief tornadoes in southeast South Dakota. Slow moving storms also produced spotty heavy rainfall, some of which that fell on areas that received heavy rainfall west of Sioux Falls in the previous night.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Sioux Falls, SD wrote its last area forecast discussion before the first event at May 31, 11:38 AM CST, 3 hours 57 minutes earlier. Its key messages:

Isolated to scattered thunderstorms should develop late this afternoon into early evening. Large hail up to half dollarand damaging winds to 60 mph would be the main hazards. A Level 1 of 5 risk for severe storms covers most of the area for this threat.
Similar to today, a conditional Level 1 of 5 risk for severe storms covers the forecast area Monday afternoon. The chance of development looks lower than today, but if a storm can form, large hail and isolated damaging winds could occur.
High chances (50-80%) for rain will persist through the bulk of next week. However, severe storm chances continue to look low (near 5% or less) through next week. The better chances for rainfall appear to be Wednesday in central SD and Wednesday night into Thursday area wide.

Area forecast discussion, May 31, 11:38 AM CST, 3 hours 57 minutes before

Area Forecast Discussion
National Weather Service Sioux Falls SD
1238 PM CDT Sun May 31 2026

.KEY MESSAGES...

- Isolated to scattered thunderstorms should develop late this
  afternoon into early evening. Large hail up to half dollarand
  damaging winds to 60 mph would be the main hazards. A Level 1
  of 5 risk for severe storms covers most of the area for this
  threat.

- Similar to today, a conditional Level 1 of 5 risk for severe
  storms covers the forecast area Monday afternoon. The chance
  of development looks lower than today, but if a storm can
  form, large hail and isolated damaging winds could occur.

- High chances (50-80%) for rain will persist through the bulk
  of next week. However, severe storm chances continue to look
  low (near 5% or less) through next week. The better chances
  for rainfall appear to be Wednesday in central SD and
  Wednesday night into Thursday area wide.

&&

.DISCUSSION...
Issued at 1235 PM CDT Sun May 31 2026

An active pattern is expected over the next several days, although
severe weather appears to remain a minor threat. Patchy heavy rain
may play the bigger role with each event.

For this afternoon and tonight, a small corridor of low level
convergence and lift will focus near and just east of the James
Valley. Clouds have cleared through early afternoon and temperatures
have risen a touch. Along with this temperature rise is a turn in
the surface winds to a more south to southwest direction vs.
southeast. This is what is aiding in this low level convergence. The
latest model soundings indicate something around 1500-2000 J/kg CAPE
but weak, disorganized shear. This suggests severe weather should
remain limited, but maybe a cell merger or two could produce a
couple of updrafts strong enough to support hail to half dollar
and wind gusts to 60 mph. Stronger storms will likely drift
east or northeast at about 15 mph, so fairly slow moving. With
this slower storm motion in mind, will need to keep an eye on
the locally heavy rain potential. A handful of the latest hi-res
models are showing small areas of 1-3" of rain with this
development. One area to keep a closer eye on will be parts of
Western Lake county, Northeast McCook and western Minnehaha
where 1-3" of rain fell late last night.

The question becomes what will drive development; will it be diurnal
heating, which would allow updrafts to start developing around 19-
21z, or will it be the weak wave which moves into the area closer to
0-3z this evening. The latest HRRR and Nam output agree with the
later start times, with the Nam indicating a stronger cap and less
development, while the RRFS and RAP kick off development a little
sooner with weaker capping. With the clearing that we are seeing in
central SD towards the James Valley we may see some development by
mid to late afternoon as destabilization is more likely. Suspect
some development between about 5-6pm.

One last thing to watch out for, if we can get mid to late afternoon
development, the LFC are marginally low and a weak convergent
boundary should be in parts of south central and southeast SD, so an
isolated funnel or two will be possible.

While a marginal risk for severe weather is in place for Monday,
confidence in the chances of development are very low. A capping
inversion may win out and for now CAPE values only running around
1000 J/kg with continued weak shear, albeit a little bit better than
today.

Another wave moves through Tuesday but weak shear and weak
instability suggest if anything can develop severe weather is very
unlikely.

Wednesday into Thursday looks like the better chance for more clouds
and better rainfall chances. Broad southerly warm advection looks to
bring in some weak elevated instability as low pressure tracks east
through ND. For now not anticipating all day rainfall but should see
off and on chances Wednesday and Thursday as this low tracks by to
the north.

Friday into Sunday will see periodic weaker waves move through the
area with a continuation of relatively weak flow aloft. This
continued weaker shear environment should keep severe weather
threats very limited.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1214 PM CDT Sun May 31 2026

Clouds continue to clear from southwest to northeast. An area of
stratiform rainfall will drift northeast through southwest MN
and northwest IA through mid afternoon. Patchy MVFR conditions
will be possible. Otherwise scattered thunderstorms will become
possible from about the James River to I-29 late afternoon
through early evening, then drift into parts of southwest MN and
northwest IA late evening and early overnight. A few of these
storms could be strong to very locally severe with locally heavy
rain likely with the stronger storms. IFR stratus and possibly
fog will fill back in late tonight into Monday morning. No
mention of fog for now as the stratus development will likely
offset this development. Regardless of fog or stratus, an
increased threat for IFR conditions.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

DISCUSSION...08
AVIATION...08

Hazardous weather outlook, May 31, 12:33 PM CST, 3 hours 2 minutes before

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
133 PM CDT Sun May 31 2026

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-
098-NEZ013-014-SDZ038>040-050-052>071-011845-
Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson-
Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury-Brookings-Gregory-
Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-
Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-Yankton-
Union-
133 PM CDT Sun May 31 2026

This Hazardous Weather Outlook is for northwest Iowa, west central
Iowa, southwest Minnesota, northeast Nebraska, central South
Dakota, east central South Dakota, south central South Dakota and
southeast South Dakota.

.DAY ONE...This afternoon and tonight.

A Level 1 of 5 risk for severe storms is in place for late this
afternoon and evening. Isolated to scattered thunderstorms should
develop late this afternoon between the James River and I-29, then
progress eastward through the evening. A very isolated stronger
storm could produce hail to half dollar and wind gusts to 60 mph.
Locally heavier rain will also be possible with small swaths of one
to three inches of rainfall.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

There is a low chance for storms again Monday afternoon. Similar to
today, confidence in storm development is low. However, if storms
can develop, isolated damaging winds and large hail would be the
main threats.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

The radar

The Sioux Falls radar (KFSD), 74 km away, was scanning. The volume nearest the first event began at 21:34 UTC.

Open the radar archive at this moment

Event by event

18 hail, 5 tornado, 1 flash flood. Local standard time, as filed.

Hail, Hanson

When: May 31, 3:35 PM CST to 3:37 PM CST
Where: Hanson County, 6.53 mi SSE of Farmer
Measured: 0.88 in hail
Reported by: Trained Spotter
Coordinates: 43.630, -97.640

Hail, Miner

When: May 31, 4:07 PM CST to 4:10 PM CST
Where: Miner County, 1.64 mi WSW of Vilas
Measured: 1.25 in hail
Reported by: Trained Spotter
Coordinates: 44.010, -97.630

Hail, Hanson

When: May 31, 4:30 PM CST to 4:33 PM CST
Where: Hanson County, 8.26 mi ESE of Alexandria
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 43.600, -97.630

Flash Flood, Hanson

When: May 31, 4:58 PM CST to 6:20 PM CST
Where: Hanson County, 7.83 mi ESE of Alexandria to 9.38 mi E of Rockport
Cause: Heavy Rain
Reported by: Public
Coordinates: 43.595, -97.643

Several public social media posts and photos indicated numerous roads in and around the community of Emery were underwater as a result of the heavy rainfall. Standing water, at least several inches deep, was also observed in many yards, including some up against structures.

Tornado, McCook

When: May 31, 5:06 PM CST to 5:07 PM CST
Where: McCook County, 1.07 mi N of Bridgewater to 1.39 mi NNE of Bridgewater
Rating: EFU
Path length: 0.47 mi
Path width: 40 yd
Reported by: Storm Chaser
Coordinates: 43.565, -97.499

A brief tornado was observed in an open field by a storm chaser around 1 mile north of Bridgewater. The tornado was estimated to touch down around one-half mile north of the Zion Bible Church on the north edge of Bridgewater. The tornado tracked northeast for less than one minute before it lifted southwest of the intersection of 436rd Avenue and 263rd Street. There were no damage indicators present to derive a rating. The average path width was estimated at 40 yards based on video evidence.

Tornado, McCook

When: May 31, 5:11 PM CST to 5:16 PM CST
Where: McCook County, 1.9 mi NE of Bridgewater to 3.08 mi ENE of Bridgewater
Rating: EF0
Path length: 1.19 mi
Path width: 75 yd
Reported by: Storm Chaser
Coordinates: 43.566, -97.469

A storm chaser witnessed a tornado develop around 2 miles northeast of Bridgewater. The tornado formed one-half mile south of 263rd Street just west of 437th Avenue. The tornado tracked northeast across open fields for around 3 minutes before it crossed 263rd Street around one-third mile west of 438th Avenue where metal roof panels were ripped off a barn. The tornado continued northeast for a couple more minutes before lifting just west of 438th Avenue. The tornado was rated EF0 with an estimated peak wind of 70 mph and an average estimated path width of 50 yards.

Hail, McCook

When: May 31, 5:16 PM CST to 5:20 PM CST
Where: McCook County, 4.86 mi N of Bridgewater
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 43.620, -97.490

Hail was jagged, with some as long as a quarter, but most of it was pea to nickel sized.

Hail, McCook

When: May 31, 5:51 PM CST to 5:57 PM CST
Where: McCook County, 1.47 mi NNE of Canistota
Measured: 1.75 in hail
Reported by: Public
Coordinates: 43.620, -97.290

Most hail was pea to quarter sized, but a few were as big as golf balls. Farm fields farther north are more damaged than those at the site.

Hail, McCook

When: May 31, 5:58 PM CST to 6:01 PM CST
Where: McCook County, 4.46 mi NE of Canistota
Measured: 1.5 in hail
Reported by: Trained Spotter
Coordinates: 43.640, -97.230

Hail damaged young crops in the fields.

Hail, Minnehaha

When: May 31, 6:20 PM CST to 6:22 PM CST
Where: Minnehaha County, 2.86 mi ENE of Pumpkin Center
Measured: 1 in hail
Reported by: Social Media
Coordinates: 43.570, -97.030

Hail, Minnehaha

When: May 31, 6:26 PM CST to 6:29 PM CST
Where: Minnehaha County, 2.86 mi WSW of Humboldt
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 43.630, -97.120

Hail, Turner

When: May 31, 6:33 PM CST to 6:35 PM CST
Where: Turner County, 4.48 mi SW of Hurley
Measured: 1 in hail
Reported by: Fire Department/Rescue
Coordinates: 43.240, -97.150

Hail, Minnehaha

When: May 31, 6:39 PM CST to 6:42 PM CST
Where: Minnehaha County, 2.94 mi SSW of Humboldt
Measured: 1 in hail
Reported by: Social Media
Coordinates: 43.610, -97.090

Hail, Minnehaha

When: May 31, 6:40 PM CST to 6:44 PM CST
Where: Minnehaha County, 2.12 mi ESE of Humboldt
Measured: 1 in hail
Reported by: Social Media
Coordinates: 43.640, -97.030

Hail, Turner

When: May 31, 6:54 PM CST to 6:57 PM CST
Where: Turner County, 2.13 mi ESE of Hurley
Measured: 1 in hail
Reported by: Public
Coordinates: 43.270, -97.040

Hail, Turner

When: May 31, 6:56 PM CST to 6:59 PM CST
Where: Turner County, 0.5 mi W of Parker
Measured: 1 in hail
Reported by: Social Media
Coordinates: 43.400, -97.140

Tornado, Minnehaha

When: May 31, 7:10 PM CST to 7:12 PM CST
Where: Minnehaha County, 2.81 mi SE of Pumpkin Center to 3.16 mi ESE of Pumpkin Center
Rating: EF0
Path length: 0.54 mi
Path width: 50 yd
Reported by: NWS Storm Survey
Coordinates: 43.527, -97.034

A tornado touched down in an open field southwest of the intersection of 266th Street and 459th Avenue. The tornado moved to the east-northeast for around one minute crossing 459th Avenue and impacting a farmstead where it damaged two barns, downed several large tree limbs, and a fence. The tornado turned a bit more northeast across 266th Street before lifting in an open field to the north. The tornado was rated EF0 with an estimated peak wind of 80 mph and an estimated average path width of 40 yards.

Hail, Clay

When: May 31, 7:17 PM CST to 7:20 PM CST
Where: Clay County, 0.86 mi SW of Wakonda
Measured: 0.88 in hail
Reported by: Trained Spotter
Coordinates: 43.010, -97.110

Hail, Turner

When: May 31, 7:36 PM CST to 7:40 PM CST
Where: Turner County, 1.71 mi NW of Davis
Measured: 1 in hail
Reported by: Social Media
Coordinates: 43.290, -97.000

Hail, Turner

When: May 31, 7:45 PM CST to 7:48 PM CST
Where: Turner County, 1.22 mi SW of Davis
Measured: 1 in hail
Reported by: Emergency Manager
Coordinates: 43.260, -97.000

Tornado, Lincoln

When: May 31, 7:50 PM CST to 7:57 PM CST
Where: Lincoln County, 8.99 mi NW of Beresford to 7.57 mi NNW of Beresford
Rating: EF0
Path length: 1.98 mi
Path width: 75 yd
Reported by: Storm Chaser
Coordinates: 43.177, -96.898

A storm chaser reported the tornado was first visible in an open field west of 466th Avenue and north of 291st Street. The tornado moved slowly southeast toward a farmstead at the intersection of 466th Avenue and 291st Street where minor tree damage was reported. The primary circulation then broadened as the tornado turned more eastward and at times exhibited smaller brief vortices. Additional minor tree damage occurred before the tornado lifted in the vicinity of 291st Street and 467th Avenue. The tornado was rated EF0 with an estimated peak wind of 75 mph and an estimated average path width of 50 yards.

Tornado, Lincoln

When: May 31, 7:58 PM CST to 7:59 PM CST
Where: Lincoln County, 7.62 mi NNW of Beresford to 7.87 mi NNW of Beresford
Rating: EF1
Path length: 0.26 mi
Path width: 75 yd
Reported by: Storm Chaser
Coordinates: 43.181, -96.841

Storm chaser video revealed a very brief tornado that moved southeast to northwest as it rotated around a much larger mesocyclone. The tornado tracked across Mount Hope Dairy, destroying one barn and damaging another before quickly lifting. Debris from the barns was scattered north of 290th Street in a southwest to northeast orientation. The tornado was rated EF1 with an estimated peak wind of 90 mph and an estimated average path width of 40 yards.

Hail, Clay

When: May 31, 8:28 PM CST to 8:31 PM CST
Where: Clay County, 5.45 mi SE of Westerville
Measured: 1 in hail
Reported by: Social Media
Coordinates: 42.870, -96.950

Hail, Union

When: May 31, 9:05 PM CST to 9:09 PM CST
Where: Union County, 4 mi SSW of Big Spgs
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 42.880, -96.640

Most hail was pea to nickel sized, but a few were quarter sized. A wall cloud was also reported about 3 to 4 miles to the west.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Tornado: A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in South Dakota in 2026 Every state in 2026 This day in weather history The tornado archive for South Dakota, 2026 Warnings in South Dakota, May 2026

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1344119, 1344120, 1344121, 1328729, 1344389, 1344405, 1344127, 1344135, 1344133, 1344134, 1344122, 1344123, 1344131, 1344132, 1344124, 1344128, 1344414, 1344125, 1344130, 1344126, 1344431, 1344438, 1344129, 1344136.