1. On April 4, 1949, a deadly tornado struck Tinker Air Force Base. The F4 tornado killed 20 people and injured over 400 others. The tornado caused extensive damage to the base, destroying over 300 buildings.

2. On April 4, 1977, the Osage Nation purchased a 43-acre parcel of land in Tulsa to build a tribal complex. The purchase marked a significant step in the tribe's efforts to regain tribal lands that were lost or taken away during the 20th century.

3. On April 4, 1933, the state legislature passed the Oklahoma Unemployment Compensation Act, providing financial assistance to unemployed individuals. The Act was later amended to include workers affected by natural disasters, such as tornadoes and floods.

4. On April 4, 1995, the Oklahoma City bombing occurred, resulting in the deaths of 168 people and injuring over 600 others. The bombing was one of the deadliest acts of domestic terrorism in US history and remains a significant event in Oklahoma's history.

5. On April 4, 1934, the Dust Bowl era officially began in Oklahoma. Severe drought, combined with poor farming practices, led to massive dust storms that swept across the state, causing significant damage to crops and property. The Dust Bowl era had a lasting impact on Oklahoma's economy and environment.