Question: The 1947 Glazier–Higgins–Woodward tornadoes were compared to the tornado that took place on what date?
Sentence (from "1947 Glazier–Higgins–Woodward tornadoes"): The 1947 Glazier–Higgins–Woodward tornadoes were a series of related tornadoes spawned by a single supercell that swept through Texas, Oklahoma, and Kansas on April 9, 1947.
Relevant evidence: No