Tornadoes in the United States
The Midwestern states are very prone to tornado activity, as they are part of "Tornado Alley." States included in the area that are hit by tornadoes the most are Oklahoma, Kansas, Missouri, Nebraska, Iowa, and South Dakota. The Midwestern States are often hit by tornadoes during the late spring and early summer months, especially the months of May and June. This is due to the aforementioned air mass moving northward into the Midwest and combining with another air mass that move southward from Canada. This creates unstable air, creating the potential for storms to strike the most during these months. The frequency begins to decrease in the middle of the summer, as the air mass moves northward into the Great Lakes states.
List of tornadoes in the May 2004 tornado outbreak sequence
The Hallam, Nebraska tornado outbreak on May 22 produced nearly 60 tornadoes across mostly Nebraska and Iowa including an F4 that tore through the town Hallam situated halfway between Lincoln and Beatrice. It was recorded as the largest tornado ever with a width of and one person was killed. However, in May 2013 it was passed by the El Reno, Oklahoma tornado with a width of 2.6 miles wide. On May 24, another tornado outbreak took place across the central United States, with about 50 tornadoes confirmed in Kansas, Illinois, Nebraska and Missouri. One person was killed in western Illinois near Winchester west of Springfield. A smaller outbreak on the May 27 produced a damaging tornado in the city of Lexington in northern Kentucky.