The Fort Collins Flood

Colorado had been plagued by drought conditions throughout the first half of the summer in 1997. The seasonal monsoon pattern that shifts winds over the Southwest to a southerly direction was late in coming. The monsoon flow brings moist air northward into Colorado. Over the Pacific Ocean, one of the greatest El Nino events in recorded history was coming to life. Meteorologists hypothesize that the developing El Nino contributed to the monsoon flow. Rain became an almost daily occurrence over the state.

On the morning of July 28 1997, residents of Fort Collins awakened to grey, cloudy skies and the fragrant, humid smell of the previous night’s showers and thunderstorms. Southeast winds blew steadily all day, pushing more tropical air into the area.

By 6 p.m., heavy showers developed over Fort Collins. With light winds aloft, the showers quickly grew into a thunderstorm that remained stationery over the city in the foothills By 7 p.m., rainfall rates of up to three inches per hour formed over the southwest side of the city and moved northward in waves, occasionally reaching 5-6 inches per hour. Eight to ten inches of rain fell across the Spring Creek watershed before 10 p.m.

The roaring floodwaters pooled behind a railroad track bed that acted as a dam, building the water level to a height of 20 feet. When the water began rushing over the top of the track bed, it quickly eroded the earthen embankment, and a wall of water 10 feet to 20 feet high rushed through two trailer parks in the city.

The Colorado State University campus was hard hit by the 500 year flood. More than 400,000 water logged books had to be shipped to a giant freezer to prevent mold damage. About half of the books were salvaged. Five people died despite valiant rescue efforts during the flood. Damage totaled over $200 million.

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