The 1918 Yellowstone River Flood: When Montana’s River Went on a Rampage

On a calm day, it's easy to look at the Yellowstone River and forget it can completely reshape life along its banks.

But in June 1918, the river did exactly that.

The water rose so high and moved with such force that a June 13, 1918, Billings Gazette headline called it the Yellowstone’s “worst rampage recorded in history.” For families, ranchers, railroad workers, and towns along the river, this was more than another high-water year. It was a disaster that tore apart bridges and left people watching the river take over places that had seemed permanent.

How the 1918 Yellowstone River Flood Set a 100 Year Record

The flood hit the upper Yellowstone River basin in early June 1918, when spring runoff sent the river to a record level near Corwin Springs, just north of Gardiner.

For decades, the 1918 flood stood as the highest recorded flow on that stretch of the Yellowstone River. The City of Livingston’s channel migration report says the river reached about 30,000 cubic feet per second during the flood.

That is an almost impossible amount of water to picture. A single cubic foot is roughly the size of a basketball. Now imagine 30,000 of them moving past one point every second.

The record lasted for more than 100 years. It was finally surpassed during the historic 2022 flooding, when the Yellowstone River at Corwin Springs rose about 2.5 feet higher than the 1918 record, according to the Livingston report.

The 1918 Flood Destroyed the Harvat Bridge in Livingston

The 1918 flood did not stay inside the riverbanks.

A U.S. Geological Survey history of flooding in the upper Yellowstone River basin documents that the Harvat Bridge in Livingston washed out during the flood. That detail alone tells you what people were up against. The Yellowstone was not simply running high. It was powerful enough to take out infrastructure communities needed to travel, move goods, and stay connected.

For towns along the river, a washed out bridge meant far more than an inconvenience. It could cut off travel, delay supplies, and leave families separated from doctors, markets, and the next town over.

The river was doing what rivers do during extreme runoff. It found the lowest path, tore through weak points, and pushed past anything people had built in its way.

How the 1918 Flood Impacted Billings, Montana

While the USGS documented the most severe physical damage upstream, Billings watched the rising water closely.

The June 13, 1918, Billings Gazette report cited by the USGS described efforts to keep the flooded Yellowstone within its banks as the river surged through the valley.

You can picture people stacking sandbags, watching the water inch closer, and hoping the river would stay where it belonged. But once the water reached that point, there was very little anyone could do to stop it.

Billings would face another unforgettable flood 19 years later, in 1937, when heavy rain, overflowing creeks, and damaged irrigation ditches sent water through city streets. The two disasters were different, but both showed how quickly water can change a community.

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Why the Yellowstone River Remains Wild Today

The Yellowstone River is the longest undammed river in the contiguous United States. It flows 671 miles from Yellowstone National Park to the Missouri River, according to the National Park Service.

That is part of what makes the Yellowstone so beautiful. It is also why its flood history matters.

The 1918 flood happened long before weather alerts, road cameras, and phones in every pocket. Families watched the sky, watched the snowpack, and watched the river. When the water began to rise, they knew exactly what was at stake.

More than a century later, the words from that old Gazette headline still land. For a few frightening days in June 1918, the Yellowstone River ran rampant.