In a year of drought, it’s really hard to imagine getting enough rain to flood. Nevertheless, 1985 wasn’t a drought year. On August 1, 1985, Cheyenne, Wyoming, was hit by a devastating flood that left a deep mark on the city. What started around 6:00pm turned into a massive supercell thunderstorm, stuck in place by the jet stream, unleashing a once-in-500-years storm. Over a three-hour period, it dumped an incredible amount of rain, with the heaviest downpour between 8:00pm and 9:00pm, when 3.51 inches fell in just one hour. The National Weather Service measured 6.06 inches total, while some areas saw up to 7.87 inches…breaking state records. Hailstones as big as 2 inches piled nearly a foot high, later forming drifts 3 to 6 feet tall as wind and water swept them away. Winds hit 70 mph, and two brief tornadoes touched down.
Unlike the quick afternoon showers typical of summer evenings in southeastern Wyoming, 
this storm parked itself over the city and let loose with unrelenting force. Forecasters described it as an “upslope system” that sparked four to six thunderstorms along the city’s western edge, leading one National Weather Service forecaster to dub it a “once in 500 years” event. In just three hours, a massive storm dumped record-breaking rainfall on Cheyenne. The heavy rainfall shattered the city’s previous three-hour record of 1.7 inches from July 15, 1896, and also topped the state record of 5.5 inches set in Dull Center, Converse County, on May 31, 1927.
Despite all the tornado warnings and blaring sirens, the twisters left no visible damage…it was the flooding that caused the real disaster. Rainwater surged into Crow Creek, Dry Creek, and downtown, creating a “wall of water” that swept through the city. Many 
residents tried to cross flooded streets along Dry Creek, where cars were swept away National Weather Service. In some neighborhoods, water rose to the top of porches and carried vehicles down streets. In the end, 12 people lost their lives, 70 were injured, and damages topped $61 million…about $145 million today.
