A near record amount of moisture in the atmosphere was available to fuel persistent storms which developed late afternoon September 19, and continued through much of the overnight and early morning of September 20.  A widespread 4 to 9 inches of rain occurred across southeast South Dakota, with some unofficial amounts up to 13 inches.

Flash Flood in TURNER, SOUTH DAKOTA
From 20-SEP-18 03:30:00 to 20-SEP-18 10:00:00 (CST-6)
Location: HOOKER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Several paved county roads were underwater around Davis, including 461st Avenue.   Several gravel roads also underwater, some impassable.

Flash Flood in LINCOLN, SOUTH DAKOTA
From 20-SEP-18 04:45:00 to 20-SEP-18 08:00:00 (CST-6)
Location: LENNOX
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Widespread flash flooding, with already around 5 inches of rainfall in the past 24 hours.

Flash Flood in LINCOLN, SOUTH DAKOTA
From 20-SEP-18 04:45:00 to 20-SEP-18 07:00:00 (CST-6)
Location: LENNOX
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Water over numerous roads in western Lincoln County.  While most roads are still passable, water is several inches deep on roads east of Lennox.

Flash Flood in CHARLES MIX, SOUTH DAKOTA
From 20-SEP-18 05:45:00 to 20-SEP-18 08:00:00 (CST-6)
Location: LAKE ANDES
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Several inches of water over 382nd Avenue starting a half mile north of Lake Andes.  The water extends over a quarter mile stretch.

Flash Flood in UNION, SOUTH DAKOTA
From 20-SEP-18 06:30:00 to 20-SEP-18 11:00:00 (CST-6)
Location: ALCESTER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Fields flooded from heavy rainfall. Water onto several gravel roads.

Flash Flood in YANKTON, SOUTH DAKOTA
From 20-SEP-18 06:35:00 to 20-SEP-18 11:30:00 (CST-6)
Location: JAMESVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Numerous roads closed across northern Yankton County due to high water, including several around Lesterville.  Several roadways washing out.

Flash Flood in HUTCHINSON, SOUTH DAKOTA
From 20-SEP-18 06:55:00 to 20-SEP-18 11:30:00 (CST-6)
Location: OLIVET
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Water was flowing across numerous roads south and east of Olivet.

Flash Flood in TURNER, SOUTH DAKOTA
From 20-SEP-18 09:23:00 to 20-SEP-18 11:30:00 (CST-6)
Location: DAVIS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Water remained over 461st Avenue north of Davis.

Flash Flood in YANKTON, SOUTH DAKOTA
From 20-SEP-18 09:55:00 to 20-SEP-18 11:30:00 (CST-6)
Location: JAMESVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Water to a foot depth was across the intersection of 294th Street and 436th Avenue. In addition, most oil roads south of Highway 46 are under water at some point.

Flash Flood in LINCOLN, SOUTH DAKOTA
From 20-SEP-18 09:42:00 to 20-SEP-18 12:00:00 (CST-6)
Location: TEA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Over 3 inches of rainfall occurred since last evening.  Significant ponding of water into yard.