A band of heavy rain developed along a warm front that lifted north through southern and central Minnesota during the afternoon and early evening of August 16. Small low-topped supercells developed within the band and produced numerous tornadoes. In addition, a large circulation was noted in southwest Minnesota during the late evening, early morning hours. This circulation produced isolated severe wind gusts near Redwood Falls, along with flooding as this circulation lasted for several hours in the vicinity.
This was the most widespread and intense rainfall event of the year in Minnesota, with 1-2 inch totals covering approximately 50,000 square miles, or about 60% of the state. Totals of greater than three inches were concentrated in a multi-county area in western and central Minnesota, generally centered on the Minnesota River. The largest official 24-hour rainfall report came from Redwood Falls, where the airport recorded 9.45 inches, and a volunteer with the National Weather Service's cooperative observer program reported 8.12 inches.
The flood waters caused significant damage to county and township roads, a section of regional railway, and county agricultural drainage systems. The cost of the damage was estimated at $675,750 in total relief.

Thunderstorm Wind in RENVILLE, MINNESOTA
From 16-AUG-17 23:52:00 to 16-AUG-17 23:54:00 (CST-6)
Location: FRANKLIN
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

A report from social media indicated that several trees were blown down in the town of Franklin.

Flash Flood in RENVILLE, MINNESOTA
From 17-AUG-17 01:00:00 to 17-AUG-17 04:00:00 (CST-6)
Location: MORTON
Flood cause: Heavy Rain
Property damage: 325.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Very heavy rainfall, and associated flooding, led to temporarily closures of Anderson Lake County Park in Franklin, along with Beaver Falls and Birth Coulee County Parks in Morton. Mack Lake County Park in Fairfax, Skalbekken County Park in Sacred Heart and Vicksburg Park in Renville were also closed due to the flooding. Several county roads in southwest Renville County were closed, and some became impassable.

Tornado in SCOTT, MINNESOTA
From 16-AUG-17 18:46:00 to 16-AUG-17 18:49:00 (CST-6)
Location: PRIOR LAKE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A tornado developed near the intersection of 145th Street NW and Mystic Lake Drive. It tracked 1.2 miles northwest. Fencing and tents were blown over, trees were uprooted, and a fish house was spun around. The maximum estimated wind speed was 70 mph.

Heavy Rain in RENVILLE, MINNESOTA
From 16-AUG-17 17:45:00 to 17-AUG-17 05:45:00 (CST-6)
Location: MINNESOTA FALLS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A measured rainfall report indicated 6.07 inches fell near Maynard, Minnesota.

Tornado in SIBLEY, MINNESOTA
From 16-AUG-17 17:26:00 to 16-AUG-17 17:33:00 (CST-6)
Location: GAYLORD
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A tornado developed east-northeast of Winthrop and tracked toward the west-northwest. It flattened some corn, uprooted trees, and caused other tree damage. Near the end of its path, it destroyed a structurally compromised barn. The maximum wind speed is estimated to have been 80 mph. Most of the path was determined through a combination of NWS storm survey and reviewing high-res satellite imagery.

Tornado in MCLEOD, MINNESOTA
From 16-AUG-17 19:08:00 to 16-AUG-17 19:09:00 (CST-6)
Location: LESTER PRAIRIE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A brief EF0 tornado on the south side of Lester Prairie produced a concentrated area of tree damage as it headed west. A funnel cloud was observed a few minutes earlier on the east side of town. Estimated max wind speed 75 mph.

Tornado in NICOLLET, MINNESOTA
From 16-AUG-17 15:46:00 to 16-AUG-17 15:52:00 (CST-6)
Location: NICOLLET
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A tornado developed south of Nicollet and moved north-northwest. It caused mainly tree damage, but did hit a farmstead and damaged a garage and grove of trees. Placement of tornado track was based on high-res satellite imagery.

Tornado in SIBLEY, MINNESOTA
From 16-AUG-17 18:21:00 to 16-AUG-17 18:22:00 (CST-6)
Location: GIBBON
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

A storm chaser provided video of a brief tornado that moved across some fields before it dissipated. No crop damage was noted.

Heavy Rain in RENVILLE, MINNESOTA
From 16-AUG-17 17:30:00 to 17-AUG-17 05:30:00 (CST-6)
Location: MORTON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A measured rainfall report indicated 6.82 inches fell near Morton, Minnesota.

Flash Flood in REDWOOD, MINNESOTA
From 17-AUG-17 01:00:00 to 17-AUG-17 04:00:00 (CST-6)
Location: REDWOOD FALLS
Flood cause: Heavy Rain
Property damage: 350.00K
Crop damage: 0.00K
Reported by: State Official

Very heavy rainfall, and associated flooding led to numerous reports of basement flooding in Redwood Falls, and surrounding communities. Flood waters caused damage to roads and drainage systems.

Funnel Cloud in SIBLEY, MINNESOTA
From 16-AUG-17 18:20:00 to 16-AUG-17 18:21:00 (CST-6)
Location: GIBBON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

A storm chaser filmed a separate funnel cloud prior to a tornado at 1821 CST. The funnel might have touched down, but it was not possible to determine this.

Thunderstorm Wind in REDWOOD, MINNESOTA
From 16-AUG-17 22:55:00 to 16-AUG-17 22:55:00 (CST-6)
Location: REDWOOD FALLS
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Trees and power lines were blown down in Redwood Falls.

Heavy Rain in BROWN, MINNESOTA
From 16-AUG-17 16:00:00 to 17-AUG-17 04:30:00 (CST-6)
Location: SEARLES
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A local observer reported 5.65 inches of rainfall in a 12 hour period.

Heavy Rain in RENVILLE, MINNESOTA
From 16-AUG-17 06:00:00 to 17-AUG-17 06:00:00 (CST-6)
Location: BECHYN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A Department of National Resources rain gauge measured 8.57 inches in 24 hours.

Thunderstorm Wind in REDWOOD, MINNESOTA
From 16-AUG-17 22:46:00 to 16-AUG-17 22:46:00 (CST-6)
Location: REDWOOD FALLS ARPT
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Tornado in NICOLLET, MINNESOTA
From 16-AUG-17 16:03:00 to 16-AUG-17 16:09:00 (CST-6)
Location: NICOLLET
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Shortly after one tornado, a second tornado developed south of Nicollet and moved north. It was observed by a local citizen, and a damage survey showed that it caused damage to corn fields. Placement of tornado track was based on high-res satellite imagery.

Tornado in NICOLLET, MINNESOTA
From 16-AUG-17 16:33:00 to 16-AUG-17 16:44:00 (CST-6)
Location: NEW SWEDEN
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The strongest tornado of the day developed in northern Nicollet County and lifted into
Sibley County. This was a multi-vortex tornado. Video shows one vortex struck a farmstead directly  causing significant damage to trees and out buildings.

Heavy Rain in RENVILLE, MINNESOTA
From 16-AUG-17 17:00:00 to 17-AUG-17 05:00:00 (CST-6)
Location: MORTON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A measured rainfall report indicated 6.49 inches fell near Beaver Falls in a 12 hour period.

Heavy Rain in REDWOOD, MINNESOTA
From 16-AUG-17 17:30:00 to 17-AUG-17 05:30:00 (CST-6)
Location: REDWOOD FALLS ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The COOP Observer for Redwood Falls, Minnesota, measured 8.12 inches of rainfall in a 12 hour period. The 8.12 rainfall total is the new state rainfall record for the date (which was officially recorded the morning of August 17th).

Tornado in SIBLEY, MINNESOTA
From 16-AUG-17 16:44:00 to 16-AUG-17 16:48:00 (CST-6)
Location: GAYLORD
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The strongest tornado of the day developed in northern Nicollet county and lifted into
Sibley county. This was a multi-vortex tornado. Video shows one vortex struck a farmstead directly causing significant damage to trees and out buildings.

Tornado in SCOTT, MINNESOTA
From 16-AUG-17 18:08:00 to 16-AUG-17 18:11:00 (CST-6)
Location: NEW PRAGUE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A weak circulation developed south of New Prague and moved across the western part of town, into Scott County, where it knocked over a tree in a cemetery on the west side of town. Just northwest of New Prague, a farm sustained minor damage to trees and outbuildings, along with a chimney that was blown over.

Tornado in NICOLLET, MINNESOTA
From 16-AUG-17 16:32:00 to 16-AUG-17 16:34:00 (CST-6)
Location: NEW SWEDEN
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A spotter reported two tornadoes near New Sweden. This tornado was confirmed by viewing high-res satellite imagery. Corn fields were damaged.

Tornado in MCLEOD, MINNESOTA
From 16-AUG-17 19:05:00 to 16-AUG-17 19:07:00 (CST-6)
Location: BISCAY
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A brief EF0 tornado between Hutchinson and Biscay. It tracked through corn fields and damaged a few trees.

Tornado in SIBLEY, MINNESOTA
From 16-AUG-17 17:15:00 to 16-AUG-17 17:19:00 (CST-6)
Location: GAYLORD
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

A tornado moved across corn fields. It was recorded on video by a storm chaser. Placement of tornado track was based on video and high-res satellite imagery.

Flash Flood in SCOTT, MINNESOTA
From 16-AUG-17 19:40:00 to 16-AUG-17 20:40:00 (CST-6)
Location: SHAKOPEE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Several cars were stalled due to a flooded roadway at the intersection of Highway 101, and Marshall Road in Shakopee.

Heavy Rain in REDWOOD, MINNESOTA
From 16-AUG-17 06:00:00 to 17-AUG-17 06:00:00 (CST-6)
Location: REDWOOD FALLS ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Redwood Falls airport ASOS measured 9.45 inches of rainfall in 24 hours.

Tornado in LE SUEUR, MINNESOTA
From 16-AUG-17 18:05:00 to 16-AUG-17 18:08:00 (CST-6)
Location: NEW PRAGUE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A weak circulation developed south of New Prague and moved across the far southwest and western part of town, into Scott County. There was minor tree damage which matched up with radar.