And the Rains Came
June 9, 1972: The rain fell in South Dakota. Rapid Creek is a tributary of the Cheyenne River and is about 86 miles long. It is located near Rapid City, South Dakota. Beginning in the afternoon on this day, 15 inches of rain fell and the creek, as well as other local waterways, overflowed and caused flooding in the region. As the rains continued to fall, the Canyon Lake Dam was clogged with debris swept in with the flooding waters. The dam failed and the resulting flood of water was responsible for 238 deaths and 3,057 injuries. Over 1,300 buildings and 5,000 cars were destroyed as the water rushed into Rapid City in what became known as the Black Hills Flood or Rapid City Flood of 1972. The property damage was listed at $160 million in 1972 dollars or $914 million today.
Earlier rains had left the soil saturated and most of the rainfall on this day had nowhere else to go but downstream. Cloud seeding experiments were being conducted by the Institute of Atmospheric Sciences west of Rapid City. There was some speculation that this may have contributed to the storms raging on this day. There is no evidence connecting the two events. There was a “low-level easterly flow which forced the moist unstable air up-slope on the hills.” This made the air rise, cool, and then release moisture in the form of more rain. Lighter than normal winds higher in the atmosphere did not help disperse the moist air nor move the thunderstorms along and so several thunderstorms dropped immense amounts of rain in the same place off and on for the entire day.
This same storm pattern affected more than just Rapid City or even South Dakota; much of the Great Plains was having the same sort of weather. In Rapid City, other winds aloft helped to keep the air patterns stable over the same region instead of moving out and on to other places. As the storms stayed in place and gathered more moisture and rained again, the over wet conditions were unable to sustain their integrity and with the collapse of the dam, the rains and the reserved water came crashing down on the city. It was one of the worst floods in the history of South Dakota and caused tremendous damage. Keystone, a nearby town was also inundated but suffered less damage and still had claims of around $1.5 million.
The National Weather Service Office in Rapid City was taking hourly surface observations and issued local storm warnings. The personnel there were not equipped or trained to make forecasts or use the technologies available to them. The total amount of rain falling on the Black Hills was 800,000 acre feet of water or 1 billion metric tons of water. But the people with this information lacked the skill to properly interpret what it would mean for the area. Today, the office has a full-time staff of meteorologists and issues both forecasts and warnings. After the flood, some businesses were permitted to stay in the flood plain but houses and motels were either raised or moved. The dam and many bridges were redesigned to prevent clogs during flooding.
There was so many [people] in trees and screaming and crying and the sparks were flying from electric wires, houses were on fire, it was just – it was hell. – Rita, survivor of the flood
I found a boy about 5 years old. He was dead, laying on some debris. I didn’t touch him or nothing, I just went back and told the authorities where he was at. Then I quit. – Alex, survivor who helped with rescue
My house is no more. You can see it over there, there’s the, well, there just isn’t anything. – unnamed survivor
A man knocked at our door and said, ‘Get out as fast as you can.’ We grabbed the children and my dad’s crippled and we picked him up and put him in the car, and just as we drove out the driveway, a big trailer started floating right across the pathway, and we just made it up the hill and that was all it was. Everything was gone. – unnamed survivor
Also on this day: Freedom of Religion – In 1628, Thomas Morton was exiled for his religious beliefs.
The Mail Didn’t Go Through – In 1772, the HMS Gaspée was run aground.
Road Trip – In 1909, the first woman to drive across the US began her journey.
Whoops – In 1873, the Alexandra Palace burned to the ground.
Jake Lingle – In 1930, the newspaperman/gangster died.