The Tornado outbreak of June 7–8, 1984 was a significant severe weather and tornado event that took place across the central United States from North Dakota to Kansas on June 7–8, 1984. The tornado outbreak produced several significant tornadoes including an F5 tornado which traveled through Barneveld, Wisconsin, in the early hours of June 8, 1984. The entire outbreak killed at least 13 people across three states including 9 in Barneveld alone.
Meteorological synopsis
A low-pressure system entered the Midwestern United States on June 7, 1984, and intensified while bringing a surge of moist and humid air coming from the Gulf of Mexico. After most of the affected areas were hit by a mesoscale convective complex earlier during the morning of June 7, the unstable atmosphere, as well as wind shear and high CAPE values produced a favorable environment for the development of extensive severe weather with possible tornadoes. Starting at around mid-afternoon, it started to produce several tornadoes across southern Minnesota and northwestern and southern Iowa including three F3s and a long-track F4 which traveled over 130 miles from extreme northern Missouri to southwest of Iowa City. That tornado killed 3 people including one in Missouri's Harrison County. Another person was killed in Ringgold County in Iowa by an F2 tornado at around 9:00pm CDT. Activity continued through the overnight hours as a new cluster of storms developed across Wisconsin near the Iowa and Illinois borders and produced strong tornadoes including the Barneveld tornado up until the early morning hours of June 8, 1984, before dissipating.
Straight-line winds in excess of 100 mph and very large hail were also reported in eastern Iowa from the storm that went on to drop the tornado in Barneveld, Wisconsin.
Confirmed tornadoes
Barneveld–Black Earth, Wisconsin
As the tornado activity calmed down across Iowa and Minnesota in which numerous strong to severe tornadoes struck those areas from mid-afternoon to mid-evening, the severe weather shifted east towards Wisconsin after dark where a tornado watch was issued at about 11:00pm CDT. By this time, most of the residents of Barneveld had gone to bed and were unaware of the tornado watch. A supercell thunderstorm, which affected portions of southeastern Iowa with a few tornadoes at around 9:00pm CDT before weakening and intensifying shortly after, entered Wisconsin from the Iowa/Illinois border at around 12:00am CDT near Dubuque. Shortly after 12:30am CDT, June 8, it produced its first tornado near Belmont in Lafayette County and lifted near Mineral Point in Iowa County about fifteen miles southwest of Barneveld.
A few minutes later, this storm system produced one of the few F5 tornadoes to hit Wisconsin, developing northeast of Mineral Point (five to six miles southwest of Barneveld). At 12:41 am CDT this F5 tornado drove through the center of Barneveld in full force, finally dissipating in northern Dane County around 1:40am CDT after traveling for 59 minutes. A strong lightning strike cut the electricity to the town just a few minutes before the tornado struck Barneveld, but it was followed by a deafening clap of thunder that awakened many residents. (It is said that the loss of power prevented the tornado siren from being activated prior to its arrival; in actuality, the town did not have a tornado siren that differed from the siren used to activate the town's volunteer fire and EMT squad. If the siren had been activated, the residents would not have known it was a tornado warning.) At its peak, the tornado was nearly a quarter-mile wide. Other tornadoes rated from F1 to F3 touched down from Columbia County to Dodge County until after 3:00am CDT when activity finally weakened.