In the early morning hours of July 31st, a line of storms originating in North Dakota began to expand and surge southeast into northeast South Dakota. As the storms moved southeast, they began to tap into warmer, more humid air and rapidly evolve into a line of severe thunderstorms. Widespread damage occurred in a wide swath extending from Long Lake in McPherson County all the way into eastern Grant County and southern Big Stone County in Minnesota.  The most extensive damage was generally found along and near US Highway 12 from Aberdeen to Milbank. Several observing stations in the path of this system measured wind speeds ranging from 70 mph to over 115 mph.  Estimated wind speeds from damage surveys indicated even stronger winds with peak speeds of 120 mph.
Over fifty communities in northeast South Dakota and the surrounding rural areas received minor to major tree and structural damage as straight line winds from 70 to 120 mph raced across the area. Webster and Waubay received the most extensive damage from the storms. Thousands of trees were snapped or uprooted, hundreds of grain bins were damaged or destroyed, hundreds of homes, businesses, and outbuildings were damaged or destroyed along with many power poles and miles of power lines downed.  Many mobile homes, campers, and boats were damaged or destroyed along with many road and business signs. Countless homes, vehicles, and campers were also damaged by fallen trees.
Thousands of acres of crops were also damaged or completely destroyed by the winds and hail. The greatest crop damage occurred in the Roslyn, Grenville, Eden, and Pickeral Lake areas in Marshall and Day counties. Many acres of corn were blown down and not able to come back. The large hail combined with the strong winds also broke out countless windows in homes and vehicles along with damaging the siding on homes. Thousands of people were left without power for up to several days. Large hay bales were moved up to 700 yards by the high winds. A semi was overturned on Highway 12 near Webster, injuring the driver. Near Milbank on Highway 12, two other semis were blown off the road resulting in injuries to both drivers. A State Forestry Specialist said it was one of the worst tree damage events he has ever seen in the Webster area. A fifty-eight year old man died two miles north of Waubay during the cleanup after the storms when he was pinned between a backhoe and a tree.

Thunderstorm Wind in EDMUNDS, SOUTH DAKOTA
From 31-JUL-08 02:40:00 to 31-JUL-08 02:40:00 (CST-6)
Location: CRAVEN
Magnitude: 51.00 MG
Reported by: Trained Spotter

Thunderstorm Wind in EDMUNDS, SOUTH DAKOTA
From 31-JUL-08 02:47:00 to 31-JUL-08 02:47:00 (CST-6)
Location: MINA
Magnitude: 54.00 MG
Reported by: Trained Spotter

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 03:02:00 to 31-JUL-08 03:02:00 (CST-6)
Location: (ABR)ABERDEEN RGNL A
Magnitude: 69.00 MG
Reported by: ASOS

Thunderstorm Wind in SPINK, SOUTH DAKOTA
From 31-JUL-08 03:02:00 to 31-JUL-08 03:02:00 (CST-6)
Location: MANSFIELD
Magnitude: 61.00 EG
Reported by: Trained Spotter

Thunderstorm Wind in SPINK, SOUTH DAKOTA
From 31-JUL-08 03:15:00 to 31-JUL-08 03:15:00 (CST-6)
Location: MELLETTE
Magnitude: 61.00 EG
Reported by: Trained Spotter

Many large tree limbs were downed in Mellette.

Thunderstorm Wind in DAY, SOUTH DAKOTA
From 31-JUL-08 03:25:00 to 31-JUL-08 03:25:00 (CST-6)
Location: PIERPONT
Magnitude: 78.00 EG
Reported by: Public

A roof was blown off of a barn and several grain bins were downed.

Thunderstorm Wind in DAY, SOUTH DAKOTA
From 31-JUL-08 03:45:00 to 31-JUL-08 03:45:00 (CST-6)
Location: ROSLYN
Magnitude: 70.00 EG
Reported by: Trained Spotter

Eighty mph winds brought many trees down.

Thunderstorm Wind in DAY, SOUTH DAKOTA
From 31-JUL-08 03:47:00 to 31-JUL-08 03:47:00 (CST-6)
Location: WEBSTER
Magnitude: 87.00 EG
Reported by: Trained Spotter

Thunderstorm Wind in DAY, SOUTH DAKOTA
From 31-JUL-08 03:55:00 to 31-JUL-08 03:55:00 (CST-6)
Location: WEBSTER MUNI ARPT
Magnitude: 87.00 EG
Reported by: Public

Many trees were downed south of Webster.

Thunderstorm Wind in DAY, SOUTH DAKOTA
From 31-JUL-08 04:05:00 to 31-JUL-08 04:05:00 (CST-6)
Location: WEBSTER
Magnitude: 78.00 EG
Reported by: Trained Spotter

Thunderstorm Wind in GRANT, SOUTH DAKOTA
From 31-JUL-08 04:05:00 to 31-JUL-08 04:05:00 (CST-6)
Location: HILAND
Magnitude: 100.00 MG
Reported by: Public

A one hundred fifteen mph wind was measured with a wind meter.

Thunderstorm Wind in CODINGTON, SOUTH DAKOTA
From 31-JUL-08 04:16:00 to 31-JUL-08 04:16:00 (CST-6)
Location: (ATY)WATERTOWN ARPT
Magnitude: 54.00 MG
Reported by: ASOS

Thunderstorm Wind in CODINGTON, SOUTH DAKOTA
From 31-JUL-08 04:20:00 to 31-JUL-08 04:20:00 (CST-6)
Location: SOUTH SHORE
Magnitude: 53.00 MG
Reported by: Mesonet

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 02:53:00 to 31-JUL-08 02:53:00 (CST-6)
Location: WESTPORT
Magnitude: 78.00 EG
Reported by: Public

A roof was completely blown off of a barn and a garage door was completely blown in.

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 03:00:00 to 31-JUL-08 03:00:00 (CST-6)
Location: WARNER
Magnitude: 87.00 EG
Reported by: NWS Storm Survey

Two miles north of Warner, one-hundred mph winds completely destroyed an attached garage and also took a small part of the roof off of the home.

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 03:00:00 to 31-JUL-08 03:00:00 (CST-6)
Location: COLUMBIA
Magnitude: 96.00 EG
Reported by: Emergency Manager

The old school gymnasium was destroyed in Columbia along with many trees downed. One fallen tree put a large hole in a home in Columbia. Also, several grain bins were destroyed near Columbia.

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 03:00:00 to 31-JUL-08 03:05:00 (CST-6)
Location: ABERDEEN
Magnitude: 70.00 EG
Reported by: NWS Employee

Eighty mph winds downed many trees and large tree branches throughout Aberdeen. One tree fell onto a car and another fell onto a house causing extensive damage.

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 03:08:00 to 31-JUL-08 03:08:00 (CST-6)
Location: PUTNEY
Magnitude: 87.00 EG
Reported by: NWS Storm Survey

One hundred mph winds severely damaged two grain bins as they were lifted off of their foundation and blown over. An old barn was also partially collapsed.

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 03:13:00 to 31-JUL-08 03:13:00 (CST-6)
Location: STRATFORD
Magnitude: 96.00 EG
Reported by: NWS Storm Survey

An empty grain bin was blown off of its foundation and into a field. The anchor bolts were bent with the concrete pulled from the anchor base. Two additional grain bins were severely dented with bent anchor bolts. An older concrete cinder block grain bin was destroyed with two others pushed off of their foundations.

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 03:16:00 to 31-JUL-08 03:16:00 (CST-6)
Location: GROTON
Magnitude: 96.00 EG
Reported by: NWS Storm Survey

An anchored single wide manufactured home was blown completely off of its foundation and destroyed. Some of the debris was blown 60 feet into another home causing damage to it.

Thunderstorm Wind in MARSHALL, SOUTH DAKOTA
From 31-JUL-08 03:30:00 to 31-JUL-08 03:30:00 (CST-6)
Location: AMHERST
Magnitude: 70.00 EG
Reported by: Trained Spotter

Several evergreens along with some power lines were blown down by eighty mph winds.

Hail in CORSON, SOUTH DAKOTA
From 31-JUL-08 00:40:00 to 31-JUL-08 00:40:00 (MST-7)
Location: BULLHEAD
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in MCPHERSON, SOUTH DAKOTA
From 31-JUL-08 02:40:00 to 31-JUL-08 02:40:00 (CST-6)
Location: LEOLA
Magnitude: 1.00 
Reported by: Law Enforcement

Hail in MARSHALL, SOUTH DAKOTA
From 31-JUL-08 03:15:00 to 31-JUL-08 03:15:00 (CST-6)
Location: HILLHEAD
Magnitude: 1.00 
Reported by: Public

Hail in DAY, SOUTH DAKOTA
From 31-JUL-08 04:15:00 to 31-JUL-08 04:15:00 (CST-6)
Location: GRENVILLE
Magnitude: 1.50 
Reported by: Trained Spotter

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 02:53:00 to 31-JUL-08 02:53:00 (CST-6)
Location: RICHMOND
Magnitude: 88.00 MG
Reported by: Public

A hoop barn was destroyed at the Aberdeen landfill. The winds were measured at 101 mph by a Davis Weather Station.

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 31-JUL-08 03:10:00 to 31-JUL-08 03:10:00 (CST-6)
Location: PUTNEY
Magnitude: 87.00 EG
Reported by: NWS Storm Survey

Large trees were uprooted by one hundred mph winds.

Thunderstorm Wind in DAY, SOUTH DAKOTA
From 31-JUL-08 03:40:00 to 31-JUL-08 03:40:00 (CST-6)
Location: WEBSTER
Magnitude: 104.00 EG
Reported by: Newspaper

The lumber yard and cabinet shop in Webster were destroyed. Power lines and poles were downed along with hundreds of trees. A semi was overturned on Highway 12 west of Webster injuring the driver. Several other injuries occurred in Day County as a result of the windstorm. The injuries were minor to moderate with scrapes and abrasions to lower back injuries and a broken collar bone.

Thunderstorm Wind in DAY, SOUTH DAKOTA
From 31-JUL-08 03:47:00 to 31-JUL-08 03:47:00 (CST-6)
Location: WEBSTER
Magnitude: 104.00 EG
Reported by: Public

A motor home was tipped over and severely damaged along with many trees downed in Webster.

Thunderstorm Wind in DAY, SOUTH DAKOTA
From 31-JUL-08 03:50:00 to 31-JUL-08 03:50:00 (CST-6)
Location: WAUBAY
Magnitude: 96.00 EG
Reported by: NWS Storm Survey

There were many trees snapped or uprooted in Waubay along with many residences sustaining roof or other structural damage.

Thunderstorm Wind in MARSHALL, SOUTH DAKOTA
From 31-JUL-08 03:50:00 to 31-JUL-08 03:50:00 (CST-6)
Location: LAKE CITY
Magnitude: 61.00 EG
Reported by: COOP Observer

Thunderstorm Wind in DAY, SOUTH DAKOTA
From 31-JUL-08 04:00:00 to 31-JUL-08 04:00:00 (CST-6)
Location: GRENVILLE
Magnitude: 74.00 EG
Reported by: Trained Spotter

Many large trees were downed at Pickeral Lake State Park.

Thunderstorm Wind in GRANT, SOUTH DAKOTA
From 31-JUL-08 04:40:00 to 31-JUL-08 04:40:00 (CST-6)
Location: MILBANK
Magnitude: 87.00 EG
Reported by: Newspaper

Many trees were downed throughout the city of Milbank. Two semis were blown off of Highway 12 near Milbank resulting in injuries to the drivers.

Thunderstorm Wind in MCPHERSON, SOUTH DAKOTA
From 31-JUL-08 02:04:00 to 31-JUL-08 02:04:00 (CST-6)
Location: LONG LAKE
Magnitude: 63.00 MG
Reported by: Mesonet

Thunderstorm Wind in MCPHERSON, SOUTH DAKOTA
From 31-JUL-08 02:16:00 to 31-JUL-08 02:16:00 (CST-6)
Location: LANGLAKE
Magnitude: 52.00 EG
Reported by: Trained Spotter

Thunderstorm Wind in MCPHERSON, SOUTH DAKOTA
From 31-JUL-08 02:30:00 to 31-JUL-08 02:30:00 (CST-6)
Location: LEOLA
Magnitude: 59.00 MG
Reported by: Mesonet