Complex sentence: The Great Flood of 1881 refers to flooding events on the Missouri River that struck Omaha, Nebraska and Council Bluffs, Iowa between April 1,1881 and April 27,1881.
Split into simpler sentences: The Great Flood of 1881 refers to flooding events on the Missouri River during the spring of 1881. The flood struck Omaha, Nebraska and Council Bluffs, Iowa between April 1,1881 and April 27,1881.