ROBERT SIEGEL, HOST:
Tomorrow in Rapid City, South Dakota, the names of 238 people will be read aloud. They died in one of the nation's worst floods. On the night of June 9th, 1972, a wall of water roared out of the Black Hills. The flash flood came as many people slept, and more than 1,300 homes were damaged or washed away all together.
South Dakota Public Broadcasting's Charles Michael Ray reports that four decades later, the town is remembering the lessons it learned from that disaster.
CHARLES MICHAEL RAY, BYLINE: I'm sitting on the banks of Rapid Creek. Some cool, clear water is running by gently below me. Right now, I could cross this creek without getting my knees wet, but 40 years ago tomorrow, a huge thunderstorm parked over the hills above this town, dropping as much as 15 inches of rain.
The surge that followed came ripping down the canyon walls, resulting in what survivors describe as a tsunami-like wall of water sweeping away nearly everything in its path: houses, cars and people.
RITA ROSALES: There were so many, and trees and screaming and crying, and the sparks were flying from electric wires. Houses were on fire. It was just - it was hell.
RAY: At the time, Rita Rosales was 20 years old and seven months pregnant. She and her mother were swept up in a surge of water while attempting to make it to higher ground.
ROSALES: And I wouldn't wish that upon nobody. That's a nightmare and a half to think that you're going to die in water, and your mom's going to go with you, you know, and you're trying to do your best to keep your mom alive.
RAY: Rosales and her mom were washed up against a building, where they held on until they were rescued, but hundreds of others weren't so lucky. By the next morning, those like Alex Koshelski(ph) were left to clean up the mess and search for bodies.
ALEX KOSHELSKI: I found a boy about five 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, and then I went - I quit.
RAY: In the aftermath of the disaster, city leaders realized it would be unwise to rebuild in the flood plain and joined with the federal government to create a buyout program for those living in flood-prone areas. Today, instead of houses lining Rapid Creek, there are a series of parks along the water. Over the years, various development projects have been proposed for the green space, but those like former Mayor Don Barnett are adamant that the parks remain where they are.
DON BARNETT: When some smooth-talker from Minneapolis comes and says, well, I want to buy 20 acres under (unintelligible) Hill, and I want to put some apartment houses down there, and I want to put a shopping center down there, we hope the city council will say not only no but hell no.
RAY: Barnett says the 1972 Black Hills flood was a wakeup call for cities across the country with buildings in flood plains. While Rapid City rebuilds itself to handle future flash floods, Mark Anderson says many other cities have not. Anderson is with the United States Geological Survey and says mountain ranges can trap thunderstorms and then funnel huge amounts of water into canyons and downstream into towns and cities.
MARK ANDERSON: The largest peak discharges of anywhere in the United States tend to be in these foothills areas. So one of the national lessons is communities at the base of foothills are at special risk.
RAY: Those who survived the 1972 Black Hills flood need little reminder of the risk. Four decades later, survivors like Rita Rosales still find thunderstorms unnerving.
ROSALES: Like when I hear it thundering and stuff, I start shaking right away. When it rains a lot, I sometimes panic.
RAY: I'm standing right now at a local fish hatchery near Rapid Creek, and I'm looking up at a bronze marker about eight feet off the ground. It shows the height of the 1972 flood at this location, about a block away from the stream. This week, several markers like this are being installed in parks up and down this stream. Hydrologists point out that while major flash floods are rare, in places like Rapid City, they will happen again. For NPR News, I'm Charles Michael Ray.