By Brad Reynolds

With centennial celebrations across the Treasure State, 1964 was a year of reflection. Montanans considered their triumphs and tribulations the past 100 years, unaware that hardship loomed on the horizon that very summer.

In the second week of June, as much as 14 inches of rain— nearly an average year’s worth—fell in a 36-hour period. Creeks and streams, already swollen from the melting of heavy snowpack, mutated into raging rivers. Roads and railroads were washed out. Homes and ranches were swept away. Two dams failed, including the 200-foot-high Gibson Dam. For the first time since its construction in 1926, water spilled over its face, flooding the Sun River below.

By the time the flooding stopped, nearly thirty thousand square miles had been affected—roughly twenty percent of the state. Damage was in the tens of millions, but the devastation to farmers and ranchers went beyond that. The floods not only wiped out their property, but their livelihoods. A dairy farm at Manchester was shut down for a month following the disaster. Volunteers had to milk cows onto the ground to prevent them from developing udder infections.

Yet the worst suffering was experienced on the Blackfeet Indian Reservation.The flood claimed 265 homes, 20,000 acres of hayland, irrigation equipment across 37,000 acres, and worst of all, the lives of 30 people.

It was the greatest natural disaster in Montana’s recorded history.