1. On May 13, 1869, a Union Pacific train arrived in Cheyenne, officially marking the completion of the first transcontinental railroad in the United States. This event was celebrated with a grand ceremony and marked a major milestone in westward expansion and the settling of Wyoming.

2. May 13, 1935, was the day that the first Big Boy steam locomotive was delivered to the Union Pacific Railroad's Cheyenne shops. The Big Boy was the largest steam locomotive ever built, weighing in at over 1.2 million pounds and measuring over 132 feet in length.

3. On May 13, 1954, a massive dust storm known as "Black Sunday" swept across parts of Wyoming and other states in the Great Plains. This event marked one of the worst dust storms in American history and highlighted the devastating effects of agricultural and land mismanagement.

4. In 1986, on May 13, a massive landslide occurred on the Gros Ventre River in Wyoming, burying a campground and killing several people. This tragic event led to the establishment of the Gros Ventre Landslide National Geologic Trail, which serves as a reminder of the powerful natural forces that shape Wyoming's landscape.

5. On May 13, 2008, an EF3 tornado struck the town of Windsor, Wyoming, causing significant damage and injuring several people. This tornado was part of a larger outbreak of severe weather that affected several states in the region and served as a reminder of the importance of preparedness and safety during severe weather events.