Udall is a city in Cowley County, Kansas, United States. The population was 794 at the 2000 census. On May 25, 1955, the deadliest tornado to ever hit the state of Kansas struck Udall at 10:35 p.m. The town was demolished. No building within the city limits was untouched, including the grain elevator and water tower. 77 people in Udall lost their lives and another 270 were injured. 192 buildings, including 170 homes were destroyed. Before striking Udall, there were no warnings issued by the Weather Bureau, so the towns residents figured that they had seen the worst of it. Unknown to them, the same tornado had just laid waste to the city of Blackwell, Oklahoma, across the border from Udall. 20 Oklahomans died and 250 were injured in Blackwell.