Twin Tornadoes

Advertisment
  • Image courtesy of National Weather Service, Omaha. This map shows the paths of the various tornadoes in the area of Pilger, Nebraska on 16th June 2014, including the twin tornadoes where one went through the town.

    Image courtesy of Storm Prediction Center, NOAA. This map shows the storm reports from 16th June 2014, showing the cluster of tornadoes in north-east Nebraska, around Pilger.

    Image courtesy of Storm Prediction Center, NOAA. This map shows the storm reports from 17th June 2014, showing the cluster of tornadoes in north-east Nebraska, around Coleridge and Laurel.

    Image courtesy of Storm Prediction Center, NOAA. This map shows the storm reports from 18th June 2014, showing the cluster of tornadoes in south-east South Dekota, around Wessington Springs.

  • Twin Tornadoes
    19.06.2014 14:58

    It is like something out of a movie, but twin tornadoes became a reality this week in the USA, three days in a row. It is unusual to have two intense tornadoes on the ground at the same time within a couple of miles of each other, within the same supercell, but for this phenomena to occur on three consecutive days is a rare thing. 

    Our Forecast Manager, Paul Knightley explains that “cyclic tornadogenesis [as the phenomena of tornado development is known] occurs when one low-level meso-cyclone starts to occlude and a new one forms. In most cases of this, the ‘new’ tornado forms several minutes after the previous one has dissipated, but occasionally, as seems to have happened this week, the ‘new’ tornado forms whilst the ‘old’ tornado is ongoing.”

    On Monday this week (16th June), twin tornadoes affected the state of Nebraska, on the central Great Plains of the USA. One of these tornadoes hit the town of Pilger, about 100 miles north-west of the city of Omaha (Nebraska’s largest city). These tornadoes killed two people and critically injured twenty others. During Tuesday and Wednesday (17th and 18th June), tornadoes also affected Verona, Wisconsin, areas near to Coleridge and Laurel, Nebraska, and Wessington Springs, South Dakota. The twin tornadoes that hit the South Dakota town, located about 125 miles north-west of Sioux Falls (South Dakota’s largest city), injured at least two people and destroyed properties, including farms, businesses, social clubs about a dozen homes. 

    Looking ahead to the risk of further tornado outbreaks in the near future, the risk seems to reduce over the coming few days, with the upper level trough, which led to the instability, that was one of the factors in causing the tornadoes, having swung northwards over Canada, allowing higher pressure to build in, at least for a time. However, this region of the world is not nicknamed Tornado Alley for no reason, so the residents and visitors will have to remain mindful of further severe weather to come. 

    By: Rachel Vince