EF1 tornado in Burt County, Nebraska

The tornado initially touched down in Burt county Nebraska about 4.5 miles west of Little Sioux Iowa. Center pivot irrigation systems were flipped and trees sustained damage in the area. Fallen tree limbs damaged homes and blocked roads and some roof damage and broken windows were noted. The storm tracked northeast and crossed the Missouri River and Interstate 29 near mile marker 97, continuing into Harrison county Iowa. The total path length was around 14 miles and it eventually achieved EF3 strength when it hit a boyscout camp in Monona county Iowa where 4 fatalities and 48 injuries occurred.

A very strong and unseasonably cold upper level low pressure system that was tracking across the northern plains brought a strong low level jet to the region during the early morning hours of June 11th. The warm and unstable air that worked north into the region helped spawn early morning severe thunderstorms across eastern Nebraska and southwest Iowa. Later that day as the upper level system worked into the central Dakotas, a cold front pushed across the region. This helped set off another round of thunderstorms that developed over east central Nebraska by late afternoon.

Isolated small supercell thunderstorms developed ahead of the cold front over eastern Nebraska, but they were quickly overtaken by a broken line of larger supercell thunderstorms, some of the heavy precipitation type, that developed along the cold front. Cell mergers and training were observed well into the evening hours as the activity quickly spread into southwest Iowa. The storms produced a total of 8 confirmed tornadoes in the Omaha/Valley warning area which covers eastern Nebraska and southwest Iowa.