A deadly and destructive outbreak sequence of 23 tornadoes struck parts of the Great Plains and the Great Lakes in late-June 1957. At least seven significant tornadoes (F2+) touched down during the outbreak sequence. The most devastating storm was a large, violent, and extremely destructive 500-yard-wide F5 tornado family that struck Fargo, North Dakota on Thursday, June 20, 1957, killing 10 people and becoming the deadliest tornado ever recorded in North Dakota. The outbreak caused 11 fatalities, 105 injuries, and $25.883 million in damage.

Meteorological Synopsis On June 20, 1957, a combination of strong instability and vertical wind shear, high storm-relative helicity (SRH), favorable storm-relative flow (SRF), and lowered lifted condensation levels (LCLs) set up over the High Plains. Boundary-layer moisture was also present, which was enhanced via evapotranspiration (ET) and moisture convergence. A shortwave ridge then centered itself over the region and, despite only modest forcing, a trough spawned a low-pressure area over Southwestern North Dakota. It then moved northeastward into the central part of the state, where temperatures and dewpoints were in the lower 80s and lower 70s respectfully. Although bulk shear was not quite high enough to support long-tracked supercells, meteorologist did indicate that an outbreak of severe thunderstorms along with a significant to violent tornado or two was possible.

That afternoon, a thunderstorm complex over Devil's Lake, North Dakota produced an outflow boundary that further enhanced the low-level convergence zone in Eastern North Dakota and Western Minnesota. An isolated supercell formed in the warm sector of the low pressure system and took advantage of this favorable environment, dropping five tornadoes, including the F5 tornado in Fargo (although the tornado family has been listed as one tornado). Four other tornadoes were confirmed on that day, although most were brief, but some were strong as well.

Confirmed tornadoes

June 20 event + Confirmed tornadoes – Thursday, June 20, 1957F#LocationCounty / ParishStateStartTime (UTC)Path length widthSummary F2S of OakesDickeyND00:30–?Damages were estimated at $25,000 (1957 USD). Tornado researcher Thomas P. Grazulis did not list this tornado as an F2 or stronger. F0SSE of WarrenCassND00:30–?Brief tornado occurred southwest of Fargo, North Dakota with little to no damage. F5Wheatland, ND to Fargo, ND to S of Winnipeg Junction, MNCass (ND), Clay (MN)ND, MN00:40–04:1010 deaths – See article on this tornado – Later analysis has determined that this was a family of at least five tornadoes. The death toll may be 12. 103 people were injured and damages were estimated at $25.250 million (1957 USD). F0Southern Fergus FallsOtter TailMN01:30–?The amount of damage is unknown. F2WNW of AshtonSpinkSD04:00–?1 death – A mobile home, four barns, and a residence were destroyed or unroofed. Damages were estimated at $25,000 (1957 USD).

June 21 event + List of confirmed tornadoes – Friday, June 21, 1957F#LocationCounty / ParishStateStartTime (UTC)Path length widthSummary F1SSW of HolyokeYumaCO08:15–?Damages were estimated at $2,500 (1957 USD). F3Waco to UticaYorkNE00:15–?An intense tornado moved eastward between the towns of Waco and Utica, destroying or damaging barns and outbuildings on 16 farms. Damages was estimated at $250,000 (1957 USD). Downbursts produced a swath of damage as well. Grazulis classified the tornado as an F2. F1BellwoodButlerNE00:30–?Damages were estimated at $250 (1957 USD). F0Northern ValparaisoSaundersNE00:52–?Damages were estimated at $30 (1957 USD). F0ESE of NorwayRepublicKS02:00–?The amount of damage is unknown. F1Western HutchinsonRenoKS03:14–?A trucking terminal was unroofed and a man may have been killed as a result. Widespread downbursts obscured the distinction between tornado and downburst damage and damage estimates are unknown as well. Grazulis classified the tornado as an F2. F0NNW of Benton to ESE of HurleySedgwickKS04:09–?Tornado caused $2,500 (1957 USD) in damage to farmlands. F1E of De Soto to Zarah to S of Lake QuiveraJohnsonKS05:30–?A destructive tornado moved directly through Zarah, west of Shawnee in the western suburbs of Kansas City. It injured two people and caused $250,000 (1957 USD) in damage.

June 22 event + Confirmed tornadoes – Saturday, June 22, 1957F#LocationCounty / ParishStateStartTime (UTC)Path length widthSummary F2Southern Kansas City to Birmingham to LibertyJacksonMO06:00–?A strong tornado moved through the eastern side of Kansas City, causing $250 (1957 USD) in damage. F0Southern Albert LeaFreebornMN16:00–?A brief tornado caused little to no damage. F2HudsonvilleOttawaMI21:30–?Major damage occurred in Downtown Hudsonville from this brief, but strong tornado. Businesses and homes were damaged or destroyed and trees were downed. Damage was estimated at $25,000 (1957 USD). This came just over one year after an F5 tornado caused major damage on the south side of town. F1Eau Claire to SW of DecaturOttawa, CassMI22:05–?This tornado moved directly through Eau Claire, causing $25,000 (1957 USD) in damage. F0Dumont LakeAlleganMI22:10–?Weak tornado passed near Dumont Lake, causing $30 (1957 USD) in damage. F2Southwestern Bay CityBayMI00:00–?Brief, but strong tornado caused heavy destruction southwest of Bay City, totaling $25,000 (1957 USD) in damage. F1SSW of CampoBacaCO03:00–?Brief tornado touchdown in the West Ute Canyon, causing $250 (1957 USD) in damage. F0N of Denver City to S of PlainsYoakumTX04:00–?Little to no damage occurred. F1FinneyHaleTX04:18–?A tornado struck the town of Finney north of Plainview and Seth Ward, causing $2,500 (1957 USD) damage.

June 23 event + Confirmed tornadoes – Sunday, June 23, 1957F#LocationCounty / ParishStateStartTime (UTC)Path length widthSummary F0CopelandGrayKS08:15–?Tornado touched down just northeast of Copeland, barely missing the town and causing little to no damage.

Fargo Tornado Family

This destructive F5 tornado tore directly through Downtown Fargo, killing 10 and injuring 103. The supercell produced the first tornado at 5:40 pm CDT near Wheatland, North Dakota. The weak F0 tornado moved east-northeast, tossing haybales and damaging crops. After , the tornado lifted and another tornado touched down just to its south. It struck the town of Casselton at F2 intensity, causing major damage. After traveling the tornado lifted and supercell continued to the east for about without producing a tornado, although a consistent wall cloud was present.

As it neared Fargo, the cell dropped another tornado over West Fargo. As it traveled east, it began to rapidly intensify, grew to , and became violent as it struck Fargo. Numerous homes, businesses, and vehicles were damaged and destroyed. One neighborhood had multiple homes that were completely swept away and all 10 fatalities occurred here. Damage at this location was rated F5. The tornado then weakened, but remained strong as it crossed the Red River into Moorhead, Minnesota, damaging more buildings and homes. The tornado then turned sharply north and dissipated after being on the ground for and injuring 103. After continuing another , the supercell dropped a fourth tornado, which quickly became a violent F4 storm as it moved eastward through Glyndon. It then turned northeastward, and produced significant tree damage along the Buffalo River before completely destroying a family farm. Significant damage was observed on a second farm before the tornado abruptly turned north and dissipated after traveling . The cell traveled about , before dropping one final F3 tornado in Dale. It traveled for , destroying a family farm as it occluded northward. A clock inside the residence stopped at 9:05 pm CDT, when the tornado struck. The tornado dissipated five minutes later at 9:10 pm CDT.

The family of tornadoes traveled a total , was wide at its peak, and was rated F5 when the Fujita scale came into effect in 1973. Although numerous studies indicate that this was a tornado family, it is officially listed as one continuous tornado. A total of 10 people were killed (some sources list the death toll as 12) and 103 others were injured with all the casualties occurring in Fargo, making it the deadliest tornado ever recorded in North Dakota. Damage was estimated $25.25 million (1957 USD).

Non-tornadic impacts Along with tornadoes, numerous reports of strong winds and large hail occurred during the period. June 20 saw baseball-sized hail south of Valley City in Barnes County, North Dakota. Later, a wind gust was recorded just southeast of Ruskin Park, South Dakota. The next day, a wind gust was recorded just northwest of Castleton, Kansas. Just after midnight on June 22 in the Kansas City metropolitan area, an was recorded in Parkville, Missouri. The strongest winds from the event were in Downtown Kansas City, where wind gusts reached as high as . The next day, a massive hailstone was documented northeast of Fort Stockton, Texas, the largest from the event.

See also List of F5 and EF5 tornadoes List of tornadoes and tornado outbreaks List of North American tornadoes and tornado outbreaks

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