Flash Flooding and Hail in South Dakota, June 26 to 27, 2018

Name: Flash Flooding and Hail in South Dakota, June 26 to 27, 2018
Start: 2018-06-26T23:15
End: 2018-06-27T12:45
Location: South Dakota

June 26 to 27, 2018 · NWS ABR · 23 events in 7 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: 23

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 ABR wrote it up.

A cold front moving in from the west brought severe weather to parts of central and north central South Dakota. Large hail up to golf ball size, damaging winds to 70 mph, along with flash flooding occurred during the morning hours. The big story was a long track destructive hailstorm and severe winds that started in southeast Dewey county and moved southeast through western Sully county and through Hughes County. The hail swath was nearly continuous and was from 2 to 5 miles wide and for nearly sixty miles. Tens of thousand of acres of crops and pastureland were destroyed by this storm along with some wildlife killed including pheasants and deer. The hail and wind also wreaked havoc on buildings, windows, and vehicles. A second destructive hail and wind storm would cross this area on June 29th.

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 Aberdeen, SD wrote its last area forecast discussion before the first event at Jun 26, 10:23 PM MST, 52 minutes earlier.

Area forecast discussion, Jun 26, 10:23 PM MST, 52 minutes before

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Hazardous weather outlook, Jun 26, 5:49 AM MST, 17 hours 26 minutes before

Hazardous Weather Outlook
National Weather Service Aberdeen SD
749 AM CDT Tue Jun 26 2018

MNZ039-046-SDZ005>008-010-011-017>023-036-037-051-271300-
Traverse-Big Stone-McPherson-Brown-Marshall-Roberts-Edmunds-Day-
Faulk-Spink-Clark-Codington-Grant-Hamlin-Deuel-Hyde-Hand-Buffalo-
749 AM CDT Tue Jun 26 2018

This Hazardous Weather Outlook is for portions of west central
Minnesota, central South Dakota, north central South Dakota, and
northeast South Dakota.

.DAY ONE...Today and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

An isolated thunderstorm or two will move in from the west
Wednesday morning. The risk for severe weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

SDZ003-004-009-015-016-033>035-045-048-271300-
Corson-Campbell-Walworth-Dewey-Potter-Stanley-Sully-Hughes-Jones-
Lyman-
749 AM CDT Tue Jun 26 2018 /649 AM MDT Tue Jun 26 2018/

This Hazardous Weather Outlook is for portions of central South
Dakota and north central South Dakota.

.DAY ONE...Today and Tonight

Thunderstorms are possible this evening and overnight with a fast
moving system. An isolated stronger storm or two could produce hail
and strong winds, which are the main threats.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

Connelly

The radar

The Bismarck radar (KBIS), 160 km away, was scanning. The volume nearest the first event began at 06:15 UTC.

Open the radar archive at this moment

Event by event

13 hail, 7 thunderstorm wind, 3 flash flood. Local standard time, as filed.

Thunderstorm Wind, Corson

When: June 26, 11:15 PM MST
Where: Corson County, 3.21 mi ESE of Athboy
Measured: 51 kt (59 mph) measured gust
Reported by: Mesonet
Coordinates: 45.550, -101.870

Thunderstorm Wind, Dewey

When: June 27, 12:15 AM MST
Where: Dewey County, 8.64 mi NNW of Parade
Measured: 52 kt (60 mph) estimated gust
Reported by: Public
Coordinates: 45.150, -101.150

Sixty mph winds were estimated.

Hail, Dewey

When: June 27, 1:10 AM MST to 1:25 AM MST
Where: Dewey County, 9.87 mi SE of Thatcher to 16.59 mi SE of Thatcher
Measured: 1.5 in hail
Reported by: Newspaper
Coordinates: 44.915, -100.793

Large hail and damaging winds destroyed many acres of crops and pastureland as a severe thunderstorm moved southeast out of Dewey into northwest Sully county.

Hail, Sully

When: June 27, 2:15 AM CST
Where: Sully County, 2.02 mi SW of Gallagher
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 44.700, -100.580

Hail, Sully

When: June 27, 2:25 AM CST to 3:30 AM CST
Where: Sully County, 8.83 mi NW of Gallagher to 7.07 mi SSE of Okobojo
Measured: 1.75 in hail
Reported by: Newspaper
Coordinates: 44.800, -100.690

Large hail and damaging winds destroyed thousands of acres of crops and pastureland as a severe thunderstorm moved out of southeast Dewey county, across Sully county and through Hughes county. Some property damage also resulted from the severe winds and hail.

Thunderstorm Wind, Hughes

When: June 27, 3:14 AM CST
Where: Hughes County, 0.49 mi E of Harrold Arpt
Measured: 50 kt (58 mph) measured gust
Reported by: Mesonet
Coordinates: 44.530, -99.720

Hail, Stanley

When: June 27, 2:20 AM MST
Where: Stanley County, 5.4 mi SW of Ft Pierre
Measured: 1 in hail
Reported by: Public
Coordinates: 44.290, -100.440

Hail, Hughes

When: June 27, 3:30 AM CST to 4:40 AM CST
Where: Hughes County, 12.24 mi NNW of (Pir)pierre Arpt to 11.77 mi ESE of De Grey
Measured: 1.75 in hail
Reported by: Newspaper
Coordinates: 44.550, -100.350

A severe thunderstorm with large hail and damaging winds came out of Sully county and tracked southeast across Hughes county destroying thousands of acres of crop and pastureland along its path. Some property damage also resulted from the severe winds and large hail.

Thunderstorm Wind, Lyman

When: June 27, 3:40 AM CST
Where: Lyman County, 3.49 mi N of Lower Brule
Measured: 61 kt (70 mph) estimated gust
Reported by: Public
Coordinates: 44.130, -99.580

Estimated seventy mph winds overturned several center pivots and flattened corn and beans.

Thunderstorm Wind, Lyman

When: June 27, 4:00 AM CST
Where: Lyman County, 0.85 mi NW of Lower Brule
Measured: 52 kt (60 mph) estimated gust
Reported by: Public
Coordinates: 44.090, -99.580

Sixty mph winds were estimated.

Hail, Lyman

When: June 27, 4:05 AM CST
Where: Lyman County, 0.85 mi NW of Lower Brule
Measured: 1 in hail
Reported by: Public
Coordinates: 44.090, -99.580

Thunderstorm Wind, Buffalo

When: June 27, 4:19 AM CST
Where: Buffalo County, 2.87 mi NE of Shelby
Measured: 54 kt (62 mph) measured gust
Reported by: Mesonet
Coordinates: 43.980, -99.140

Flash Flood, Hughes

When: June 27, 4:40 AM CST to 9:40 AM CST
Where: Hughes County, 9.31 mi SE of De Grey to 11.45 mi SE of De Grey
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 44.190, -99.780

Heavy rains caused flash flooding over mainly west bend road for several hours.

Hail, Lyman

When: June 27, 5:20 AM CST
Where: Lyman County, 4.57 mi NE of Kennebec
Measured: 1 in hail
Reported by: Public
Coordinates: 43.950, -99.810

Hail, Stanley

When: June 27, 4:32 AM MST
Where: Stanley County, 5.4 mi SW of Ft Pierre
Measured: 1 in hail
Reported by: Public
Coordinates: 44.290, -100.440

Hail, Lyman

When: June 27, 5:38 AM CST
Where: Lyman County, 10.02 mi E of Mc Clure
Measured: 1.25 in hail
Reported by: Public
Coordinates: 44.100, -100.050

Hail, Lyman

When: June 27, 5:48 AM CST
Where: Lyman County, 4.94 mi NNE of Oacoma
Measured: 1 in hail
Reported by: Public
Coordinates: 43.870, -99.380

Flash Flood, Stanley

When: June 27, 5:09 AM MST to 8:09 AM MST
Where: Stanley County, 7.87 mi NNW of Ft Pierre to 6.67 mi W of Ft Pierre
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 44.445, -100.457

Heavy rains resulted in several flooded county roads for several hours.

Hail, Lyman

When: June 27, 6:10 AM CST
Where: Lyman County, 7.6 mi N of Presho Muni Arpt
Measured: 1.25 in hail
Reported by: Public
Coordinates: 44.030, -100.030

Hail, Lyman

When: June 27, 6:36 AM CST
Where: Lyman County, 4.57 mi NE of Kennebec
Measured: 1.5 in hail
Reported by: Public
Coordinates: 43.950, -99.810

Thunderstorm Wind, Lyman

When: June 27, 6:55 AM CST
Where: Lyman County, 1.38 mi S of Reliance
Measured: 56 kt (64 mph) estimated gust
Reported by: Emergency Manager
Coordinates: 43.860, -99.600

Several billboards were blown over by estimated sixty-five mph winds.

Hail, Lyman

When: June 27, 7:23 AM CST
Where: Lyman County, 1 mi E of Oacoma
Measured: 1.75 in hail
Reported by: Trained Spotter
Coordinates: 43.800, -99.380

Flash Flood, Lyman

When: June 27, 9:45 AM CST to 12:45 PM CST
Where: Lyman County, 0.78 mi E of Oacoma to 0.84 mi E of Oacoma
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 43.798, -99.385

Flash flooding from heavy rains occurred east of Oacoma with parts of roads underwater.

What these are

Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
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.

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

The same day elsewhere

Every storm in South Dakota in 2018 Every state in 2018 This day in weather history Warnings in South Dakota, June 2018

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 2026-10-01. Each event’s entry at NCEI: 770907, 770908, 770932, 770894, 770934, 770909, 770895, 770935, 770905, 770911, 770896, 770913, 770893, 770897, 770899, 770900, 770901, 770867, 770902, 770903, 770906, 770904, 770889.