Thunderstorms produced large hail, damaging winds, and flash flooding in southeast South Dakota, near and north of Interstate 90, during the evening of May 5th. The flash flooding continued past midnight on May 6th.

Hail in DAVISON, SOUTH DAKOTA
From 05-MAY-12 17:45:00 to 05-MAY-12 17:45:00 (CST-6)
Location: BETTS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in DAVISON, SOUTH DAKOTA
From 05-MAY-12 17:48:00 to 05-MAY-12 17:48:00 (CST-6)
Location: MITCHELL
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds caused tree damage, including branches blown down.

Thunderstorm Wind in DAVISON, SOUTH DAKOTA
From 05-MAY-12 17:55:00 to 05-MAY-12 17:55:00 (CST-6)
Location: MITCHELL
Magnitude: 68.00 MG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Thunderstorm winds broke a large sign at an Interstate 90 exit, and caused tree damage.

Hail in SANBORN, SOUTH DAKOTA
From 05-MAY-12 18:04:00 to 05-MAY-12 18:04:00 (CST-6)
Location: ARTESIAN
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in HANSON, SOUTH DAKOTA
From 05-MAY-12 18:21:00 to 05-MAY-12 18:21:00 (CST-6)
Location: FULTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in HANSON, SOUTH DAKOTA
From 05-MAY-12 18:47:00 to 05-MAY-12 18:47:00 (CST-6)
Location: PLANO
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in MINER, SOUTH DAKOTA
From 05-MAY-12 18:52:00 to 05-MAY-12 18:52:00 (CST-6)
Location: EPIPHANY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in HANSON, SOUTH DAKOTA
From 05-MAY-12 19:00:00 to 05-MAY-12 19:00:00 (CST-6)
Location: PLANO
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Large hail was accompanied by heavy rain. Local power went out during the storm.

Flash Flood in HANSON, SOUTH DAKOTA
From 05-MAY-12 19:00:00 to 05-MAY-12 23:00:00 (CST-6)
Location: PLANO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Persistent heavy rain from thunderstorms caused flash flooding of fields, rural roads, and at least one basement.

Hail in KINGSBURY, SOUTH DAKOTA
From 05-MAY-12 19:10:00 to 05-MAY-12 19:10:00 (CST-6)
Location: BADGER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LAKE, SOUTH DAKOTA
From 05-MAY-12 19:24:00 to 05-MAY-12 19:24:00 (CST-6)
Location: WINFRED
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Thunderstorm Wind in LAKE, SOUTH DAKOTA
From 05-MAY-12 19:41:00 to 05-MAY-12 19:41:00 (CST-6)
Location: ORLAND
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm winds caused considerable tree damage, including some trees blown down.

Hail in LAKE, SOUTH DAKOTA
From 05-MAY-12 19:42:00 to 05-MAY-12 19:42:00 (CST-6)
Location: JUNIUS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Large hail was accompanied by heavy rain, and estimated 45 mph wind gusts.

Hail in BROOKINGS, SOUTH DAKOTA
From 05-MAY-12 19:43:00 to 05-MAY-12 19:43:00 (CST-6)
Location: BRUCE
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in LAKE, SOUTH DAKOTA
From 05-MAY-12 19:45:00 to 05-MAY-12 19:45:00 (CST-6)
Location: MADISON
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm Wind in LAKE, SOUTH DAKOTA
From 05-MAY-12 19:49:00 to 05-MAY-12 19:49:00 (CST-6)
Location: MADISON
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm winds caused tree damage, including a few trees blown down.

Thunderstorm Wind in MCCOOK, SOUTH DAKOTA
From 05-MAY-12 19:50:00 to 05-MAY-12 19:50:00 (CST-6)
Location: SALEM
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm winds overturned a semi truck.

Hail in BEADLE, SOUTH DAKOTA
From 05-MAY-12 20:10:00 to 05-MAY-12 20:10:00 (CST-6)
Location: CAVOUR
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LAKE, SOUTH DAKOTA
From 05-MAY-12 20:12:00 to 05-MAY-12 20:12:00 (CST-6)
Location: MADISON MUNI ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Large hail was accompanied by estimated 60 mph wind gusts.

Thunderstorm Wind in LAKE, SOUTH DAKOTA
From 05-MAY-12 20:12:00 to 05-MAY-12 20:12:00 (CST-6)
Location: MADISON MUNI ARPT
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds caused tree damage. The winds were accompanied by quarter size hail.

Hail in LAKE, SOUTH DAKOTA
From 05-MAY-12 20:13:00 to 05-MAY-12 20:13:00 (CST-6)
Location: JUNIUS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in MOODY, SOUTH DAKOTA
From 05-MAY-12 20:30:00 to 05-MAY-12 20:30:00 (CST-6)
Location: COLMAN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Large hail followed estimated 50 mph thunderstorm wind gusts.

Hail in BRULE, SOUTH DAKOTA
From 05-MAY-12 20:30:00 to 05-MAY-12 20:30:00 (CST-6)
Location: EAGLE
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in LAKE, SOUTH DAKOTA
From 05-MAY-12 20:30:00 to 05-MAY-12 20:30:00 (CST-6)
Location: MADISON
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm winds blew a steel pole shed building across a road. The winds also caused tree damage. The winds were accompanied by heavy rain.

Thunderstorm Wind in MOODY, SOUTH DAKOTA
From 05-MAY-12 22:22:00 to 05-MAY-12 22:22:00 (CST-6)
Location: FLANDREAU MUNI ARPT
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds flattened a billboard sign with a metal frame.

Thunderstorm Wind in LAKE, SOUTH DAKOTA
From 05-MAY-12 22:30:00 to 05-MAY-12 22:30:00 (CST-6)
Location: WENTWORTH
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm winds caused tree damage, including several branches blown down. The winds were accompanied by heavy rain and by half inch diameter hail that covered the ground.

Flash Flood in LAKE, SOUTH DAKOTA
From 05-MAY-12 22:45:00 to 06-MAY-12 02:45:00 (CST-6)
Location: ORLAND
Flood cause: Heavy Rain
Property damage: 2.00M
Crop damage: 0.00K
Reported by: Broadcast Media

Heavy rainfall of up to 6 inches caused flash flooding of numerous roads, parks, fields, other low areas, and buildings including homes. At least 90 homes were heavily damaged in Madison by the flooding, including at least two with basement walls washed out. A basement wall of a dentists business was also washed out and the basement flooded with 9 feet of water. Numerous personal possessions in flooded homes and businesses were destroyed. The flash flooding included Memorial Creek, and there was a fatality when an out of state visitor drowned when attempting to cross the flooded creek. While this fatality and most of the damage was in Madison, many rural roads and fields were flooded in the area, and east to near the town of Wentworth.

Thunderstorm Wind in MOODY, SOUTH DAKOTA
From 05-MAY-12 21:00:00 to 05-MAY-12 21:20:00 (CST-6)
Location: FLANDREAU
Magnitude: 65.00 EG
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm winds caused widespread damage in the south part of Flandreau. Roofs on homes, apartment buildings, and other buildings were blown off or damaged. The roof of a large church was blown off, and parts of the roof damaged nearby homes. The Flandreau city office building had part of its south wall blown off, resulting in interior damage to ceiling tiles and insulation. Siding on other walls of this building and on numerous homes was damaged. Tree damage was widespread, including several trees blown down or uprooted. The winds blew down power lines, leaving parts of the city without power for almost three hours.

Thunderstorm Wind in MOODY, SOUTH DAKOTA
From 05-MAY-12 20:57:00 to 05-MAY-12 20:57:00 (CST-6)
Location: FLANDREAU
Magnitude: 63.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet