1. The Blackfoot Massacre: On April 1, 1870, an armed conflict occurred between a group of approximately 173 United States Army soldiers and a band of Blackfoot Indians, resulting in the deaths of more than 70 Blackfoot individuals, including women and children. The incident was later known as the Blackfoot Massacre and is considered one of the bloodiest conflicts in Idaho history.

2. Idaho becomes a state: On April 1, 1890, Idaho officially became the 43rd state of the United States. It was the first state to enter the Union in that year, with Wyoming and Utah following later that summer.

3. The Great Fire of 1910: On April 1, 1910, a massive forest fire began in northeastern Washington and quickly spread across the Idaho border, eventually destroying millions of acres and killing 85 people. The disaster is remembered as one of the worst wildfires in American history and served as a catalyst for the modern practice of forest fire prevention and control.

4. Record-breaking snowfall: On April 1, 1975, an intense winter storm hit Idaho, causing a record-breaking snowfall of 30 inches in just one day. The storm paralyzed the state's transportation networks and caused widespread power outages, leading to a state of emergency declaration.

5. Potato Harvest Festival: Since 1937, the city of Shelley, Idaho has celebrated its annual Spud Day festival on the first Saturday in September, which marks the start of potato harvest season in the region. The festival features potato sack races, mashed potato wrestling, and a parade of potato-themed floats and decorations, among other activities.