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Black Hills Flood of 1972

One of the most detrimental floods in the history of South Dakota took place on June 9th-10th 1972 (Nair, Hjelmfelt, and Pielke 1753). This flood was the 1972 Black Hills Flood, taking place in the Black Hills of Rapid City,South Dakota. The Black Hills Flood also known as the Rapid City Flood, not only hit Rapid city although the main object, it caused flooding in “Battle Spring Creek, Rapid, and Boxelder Creeks” (Carter, Williamson, and Teller).

What Caused the Flood
The occurrence of such a devastating flood was caused by the excessive and rare amount of rainfall the area received. A few days before the happening of the Rapid City Flood “earlier rains had left the soil saturated, increasing the amount of runoff of the flood to come” (Cater, Williamson, and Teller)on the afternoon of the 9th substantial rains began to fall on the area, caused by “an almost stationary group of thunderstorms” (Carter, Williamson, and Teller). The unusual amounts of rain were caused by:

A strong low- level easterly flow which forced the moist unstable air up-slope on the hills. This sustained orographic effect helped the air to rise, cool, and release its moisture in repeating thunderstorms. Another contributing factor was the unusually light winds at a higher atmospheric levels which did not disperse the moist air nor move the thunderstorms along to prevent an extreme concentration of rainfall. (Carter, Williamson, and Teller)

According to Thompson the air pattern causing this storm was noticed in big measure over the Great Plains, with a minor scale to the east of the Rockies. There were only what appeared to be light winds, so nothing indicated that there was a huge storm underway. Thompson further indicates that a cold high pressure region was pushed from Canada into the Great Lakes region leading into the western part of South Dakota. A “metro-scale cloud mass” from Colorado also moved towards Rapid City (164). One of the cloud masses amplified the “mid-level moisture over Rapid City,” while the other mass caused the pressure to stay, as the high pressure pushed downward, thus creating the right conditions to produce rainfall (Thompson 164-165). The rainfall from the upper “cloud mass” above the Black Hills formed into new smaller masses downwind which reprocessed the rain allowing for the constant rainfall (Nair, Hjelmfelt, Pielke 1756). The storm was categorized by Nair, Hjelmfelt, and Pielke as “convective cells of high precipitation efficiency a characteristic of tropical precipitation systems (1753). The immense precipitation was based over the “Rapid, Boxelder, Spring, and Battle Creeks,” creating run-off, along these creeks which lead to flooding throughout the surrounding areas (Nair, Hjelmfelt, and Pielke 1753).

The intense rain began on the afternoon of June 9th and continued until after midnight on June 10th. The immense amount of rain the Black Hills received during the thunderstorms ranged from 4 to 15 inches (Carter, Williamson, and Teller). Causing Rapid Creek and surrounding creeks to overflow, along with massive amounts of runoff resulting in flood waters. The run-off carried rubble to the Canyon Lake Dam creating a barrier in front of its spillway (Carter, Williamson, and Teller). This resulted in the “increase in depth of water behind the dam of 11 to 12 feet,” which caused the release of more water adding to the already moving floodwater's (Thompson 167). The flash flood hit Rapid City the hardest around midnight on June 9th; the flood waters also hit the small townKeystone nearby (Carter, Williamson, and Teller).

Damage
Being as this was one of the worst floods in the history of South Dakota it caused a tremendous amount of damage. The flood waters displaced large rocks, trees, trailers, vehicles, and carried homes away (Thompson166). In Rapid City the flood resulted in the deaths of “238 including 5 missing,” 14 of the deaths were trained professionals (Rapid City). The flood resulted in over 3,000 people being injured. A total of 1,335 homes were ruined, and 2,820 homes were damaged. More than 200 businesses were ruined, and around 5,000 cars were demolished. The damages in Rapid City totaled 66 million dollars in 1972 dollar value (Rapid City). As for Keystone “eight people were killed and much of the town was washed away,” (Carter, Williamson, and Teller). The damage in Keystone totaled around $1.5 million (Rapid City).The total cost of the 1972 Black Hills flood totaled $165 million, including infrastructure, and utilities. The total amount of rain the Black Hills received was “800,000 acre feet” equal to “1 billion metric tons of water,” (Rapid City).

TheNational Weather Service Office (NWS) in Rapid City in 1972 was taking hourly surface observations, issuing local storm warnings and providing local forecasts to the media. The personnel in Rapid City were not properly trained to make forecasts or use the technologies available to them (National Weather Service). They lacked access to vital weather information to warn the area citizens.

Than and Now
The Rapid City National Weather Service is now a forecast office with a full time staff of meteorologists who issue both forecasts and warnings for northeastern Wyoming and the western third of South Dakota. In 1972, the National Weather Service (NWS) office in Rapid City did not have a teletype system to broadcast warnings. They instead used a one-way telephone hotline to the media to broadcast the warnings. Today warnings are sent to a regional site where they are sent to the National Oceanic and Atmospheric Administration (NOAA) Weather Wire System satellite. NWS forecasters use the state radio system to notify 911 dispatchers and emergency personnel. This warning is also passed on to the Emergency Alert System(EAS).

In the aftermath of the 1972 flood, short-term and long-term programs were placed into effect. Many businesses were permitted to stay in the flood plain, but houses and motels were either raised or moved due to the unlikelihood that a flood would occur while a person may be sleeping. The majority of the flood plain was made into large parks. Canyon Lake Dam and most bridges were redesigned to prevent debris clogs during flooding. Due to their malfunction in 1972 they have been redesigned.

Victoms
Victims lost precious memories as stated in the Rapid City newspaper. An excerpt from the newspaper reads, “Operation Family Treasure’ may provide hope for people.’ For those who have given up all hope about finding a priceless photo album or sheet of important personal papers there may be a happy ending with “Operation Family Treasure,” a clearing house for irreplaceable items run by the Rapid City Jaycees in conjunction with the Office of Civil defense. Flood disaster victims advised on tax breaks.” (www.rcgov.org)  Victims of lost memories are offered a small hope that this gift will return lost memories.

2012 marks the 40 year anniversary of the fateful flood. Survivors remark on the horrific events. Rita, who was 20 at the time, describes the scenes in her eyes, "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," she says. Rita was seven months pregnant at the time of the tragedy. She describes her fears as, "I wouldn't wish that upon nobody," she says. "That's a nightmare and a half to think that you're going to die in water and your mom is gonna go with you and you're trying to do your best to keep your mom alive." Rita and her mother were swept against a building and thankfully rescued. There were others with the same nightmares while others were worse. Good Samaritans, like Alex were left to clean up the mess and search for the less fortunate. He describes a gruesome scene, "I found a boy about 5 years old," Alex says. "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 (Ray)." This was only the beginning of the aftermath.