Samuel Thomas Hauser, territorial governor of Montana from 1885 to 1887, formed the Missouri River Power Company in 1894 and won the approval of the United States Congress to build a dam, the Hauser Dam, two miles below Stubb's Ferry on the Missouri River. It was a steel dam built on masonry footings on top of gravel, with the ends of the dam anchored in bedrock on either side of the river. The dam was 630 feet long and 75 feet high. Because 300 feet of the center section of the dam was built on a gravel riverbed and the rest on bedrock, sheet pilings were driven 35 feet into the riverbed and the steel of the dam attached to the pilings. The upstream face of the dam was covered in concrete, and a 20-foot deep layer of volcanic ash laid down on the upstream riverbed extending 300 feet from the dam to discourage seeping. The 10 horizontal turbines in the powerhouse delivered 14,000 kilowatts of power. The total cost of the dam at that time was $1.5 million. It became operational on February 12, 1907.

On April 14, 1908, at about 2:30 PM, Hauser Dam failed after water pressure undermined the masonry footings. The first sign of trouble was when silt-heavy water began gushing from the base of the dam near the powerhouse. A power company employee, spotting the problem, ran into the powerhouse and told everyone to flee for their lives. About 15 minutes later, the masonry footings gave way, causing the upstream section of the dam to settle and a 30-foot wide breach to open in the dam. The water pouring through the breach further undermined the dam's footing, and six minutes later a 300-foot wide section of the dam tore loose. A surge of water 25 to 30 feet high swept downstream. The supervisor of construction, Martin Gerry, received a telephone call from the dam operators alerting him to the dam's destruction. He immediately sent telegrams to all towns and cities downstream, warning them of the coming flood. A Great Northern Railway locomotive was dispatched to the city of Great Falls, 70 miles downstream, warning stations along the way about the dam break. The flood reached the small town of Craig, Montana, around 7:00 PM, but the narrow canyons of the Missouri River above the town helped hold back part of the floodwaters. The residents of the town received plenty of warning, and were evacuated. The famous iron Craig Bridge, normally 25 feet above water, had more than 2 feet of water over its deck and was feared doomed, but it held. The Great Northern Railway tracks from Craig to Ulm were under water. Damages were estimated at more than $1 million.
https://en.wikipedia.org/wiki/Hauser_Dam