Thunderstorms over southeast South Dakota from late morning to the start of the evening on May 10th produced several tornadoes, including one that caused injuries and severe damage in Delmont in Douglas County. The thunderstorms also produced large hail, damaging winds, and flash flooding in locations extending to the eastern border of the state.

Hail in CHARLES MIX, SOUTH DAKOTA
From 10-MAY-15 09:05:00 to 10-MAY-15 09:05:00 (CST-6)
Location: RAVINIA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Tornado in CHARLES MIX, SOUTH DAKOTA
From 10-MAY-15 09:21:00 to 10-MAY-15 09:34:00 (CST-6)
Location: WAGNER
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A tornado formed and moved over fields, damaging some trees,  before crossing into Douglas County.

Tornado in DOUGLAS, SOUTH DAKOTA
From 10-MAY-15 09:34:00 to 10-MAY-15 09:53:00 (CST-6)
Location: DELMONT
Tornado F-scale: EF2
Property damage: 1.50M
Reported by: NWS Storm Survey

A tornado, crossing into Douglas County from Charles Mix County, destroyed or damaged 84 structures in and near Delmont, and injured 9 people in Delmont. About 50 of the homes and other structures were destroyed or severely damaged. The damage included numerous small farm buildings totally destroyed, most at four farms south of Delmont, several houses severely damaged, a large and 100 year old church severely damaged, and a newly constructed fire hall destroyed. Power lines and poles were down and the town was without power and water for two days. 100 residents were displaced.

Tornado in HUTCHINSON, SOUTH DAKOTA
From 10-MAY-15 10:15:00 to 10-MAY-15 10:17:00 (CST-6)
Location: DIMOCK
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A tornado formed and moved north, quickly crossing into Davison County. The tornado caused no reported damage.

Tornado in DAVISON, SOUTH DAKOTA
From 10-MAY-15 10:17:00 to 10-MAY-15 10:23:00 (CST-6)
Location: ETHAN
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

A tornado, crossing into Davison County from Hutchinson County, moved north and caused no reported damage before dissipating.

Hail in HANSON, SOUTH DAKOTA
From 10-MAY-15 11:35:00 to 10-MAY-15 11:35:00 (CST-6)
Location: PLANO
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Flood in LINCOLN, SOUTH DAKOTA
From 10-MAY-15 14:15:00 to 10-MAY-15 17:15:00 (CST-6)
Location: CANTON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Heavy rain caused local flooding of ditches along South Dakota Highway 18.

Hail in UNION, SOUTH DAKOTA
From 10-MAY-15 14:19:00 to 10-MAY-15 14:19:00 (CST-6)
Location: JEFFERSON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Funnel Cloud in LAKE, SOUTH DAKOTA
From 10-MAY-15 15:08:00 to 10-MAY-15 15:08:00 (CST-6)
Location: NUNDA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A brief funnel cloud was observed.

Flash Flood in LINCOLN, SOUTH DAKOTA
From 10-MAY-15 15:28:00 to 10-MAY-15 18:30:00 (CST-6)
Location: HARRISBURG
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy rain caused flash flooding of some roads, including 275th Street where water from flooded ditches ran over the road.

Heavy Rain in LINCOLN, SOUTH DAKOTA
From 10-MAY-15 14:45:00 to 10-MAY-15 15:45:00 (CST-6)
Location: SIOUX FALLS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Heavy rain was measured at 2.10 inches.

Hail in BEADLE, SOUTH DAKOTA
From 10-MAY-15 16:12:00 to 10-MAY-15 16:12:00 (CST-6)
Location: HURON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Funnel Cloud in MCCOOK, SOUTH DAKOTA
From 10-MAY-15 17:53:00 to 10-MAY-15 17:53:00 (CST-6)
Location: CENTER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A brief funnel cloud was observed.

Tornado in MINER, SOUTH DAKOTA
From 10-MAY-15 18:16:00 to 10-MAY-15 18:17:00 (CST-6)
Location: CANOVA
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

A brief tornado caused no reported damage.