About the Flood
On June 9, 1972, one of the most devastating floods in the nation's history swept through Rapid City, SD, and nearby communities. More than 10 inches of rain fell in just over six hours, producing flooding on Rapid Creek and several other Black Hills streams. The swollen streams rushing toward Rapid City and the failure of Canyon Lake Dam combined to send a wall of water through the community.
By daybreak on June 10, 1972, 238 lives were lost and over 3000 people were injured. Memorial Park, a large park in the center of Rapid City with a small lake, flower gardens, fountain and a memorial with names of the 238 people was created in tribute to those who perished.
Although there have been many floods recorded since settlement of the Black Hills, the 1972 flood was especially destructive. Extraordinary weather conditions have been blamed for the storm that sent torrents of rain over the Black Hills that night. Heavily saturated soil from previous rains and a stationary front that poured inches of rain in a few hours resulted in extreme run-off and the swollen streams. Many weather experts refer to the 1972 flood as a hundred-year flood. Evidence of very large prehistoric floods ("paleofloods") in the Black Hills exists, including at least two that exceeded the 1972 flood, about 440 and 1,000 years ago.
The damage to Rapid City was extreme. The 1973 U.S. Senate Subcommittee on Disaster Relief estimated the cost of physical destruction in excess of $100 million and approximately 3,100 acres of land were affected by the flood water and fires from ruptured gas lines within Rapid City.
To prevent a re-occurrence of this tragedy the city of Rapid City established a floodplain. A beautiful greenway and bike path now meander through the city alongside the once destructive Rapid Creek. In 2007, the city of Rapid City formed a Floodplain Development Policy Committee to address citizen concerns about development in the floodplain.
Death and Injury
Deaths = 238, including 5 missing.
Includes 3 National Guardsmen, 3 firefighters, 7 airmen from Ellsworth Air Force Base, 1 police reserve officer, and other rescuers
Injured = 3,057, including 118 hospitalized
Homes destroyed: 770 permanent homes, 565 mobile homes
Homes damaged: 2,035 permanent homes, 785 mobile homes
Businesses destroyed: 36
Businesses damaged: 236
Vehicles destroyed: 5,000
Total Damages = $165 million, throughout the Black Hills
Rapid City = $35.1 million in residential damage and $30.9 million in commercial damage
Box Elder = $1.2 million residential, $75,000 commercial
Keystone = $137,000 residential, $1.5 million commercial
Utilities = $10.3 million
Roads and Bridges = $35.4 million
Rural = $6.2 million
Tourism income lost = $30 million
Other economic losses = $12 million
- Total estimated amount of water dumped by the June 9, 1972 storm: 800,000 acre feet, or the equivalent of 14.5 Pactola Reservoirs
- Put another way: 1 billion metric tons of water (by conservative estimate)
- Heaviest rainfall was 15 inches in six hours at Keystone.
- One location in the Black Hills reported 4 inches in 30 minutes.
- More than 10 inches fell over a 60-square-mile area.
The most common rumor: the false report that the dam at Pactola Reservoir had burst, heard nationwide.
Most unusual rumor: That crocodiles had escaped into Black Hills streams from Reptile Gardens. No creatures escaped from the popular tourist attraction, although some rattlesnakes drowned.
Information from the Rapid City Journal's May 17, 1992 Special Edition on the "Flood of 1972 - 20 Years Later".
USGS and National Weather Service Information
Additional information regarding the flood and efforts to create a warning system for future flooding is available on the USGS website.
A timeline, weather summary, statistics, and technology change and mitigation effort information can be found on the National Weather Service website.
1972 Flood Commemoration Map
An interactive map created by the City of Rapid City GIS department shows users the location of damaged and destroyed homes, the locations of the greenway that was created as a result of the flood, and the areas directly impacted by the floodwaters.