Chief Meteorologist Emeritus Bob Riggio chats with Chief Meteorologist Brant Beckman about the changes in forecasting weather since the 1972 flood.
Riggio says, “From the flood to now, a thousand times improvement in the warning system, thousand times improvement.”
Riggio remembers, “Back then…urgent. The word that comes to me a lot, Brant, when I think back when I was here, June 9th, 1972, is the word urgent. At what point did the folks that were living along the creek as were close to this creek or living near it. When did they realize the situation was urgent for them to move to higher ground? For them to leave their homes and move to higher ground? At what point in time and for many of them that just came way too late, way too late.”
Beckman points out, “I think when you’re talking about unprecedented events and that even goes for things that happen today around the world, when you have something that hasn’t happened before…yes…you learn a lot, but it doesn’t give you a lot of solace even after the fact. That this event is still happening like, man, I wish there was something I could have done. I can not imagine. Bob, when I drove here, when I first came here to Rapid, I saw this beautiful greenery. There’s these great big parks. This is amazing. I can’t believe that the city would put aside all this area for greenery. And this was when I was just 12 years old with my grandfather coming up here to Rapid City, he says, ‘Well, you know, there was a flood here.’ I said, ‘Okay, there was a flood.’ But not that much. I mean that that’s half the city.”
Riggio continues, “The population in the 70’s for Rapid City, I would say just over 40,000 people. In that one night, 238 people lost their life in that one night. Over 3000 people were injured. Many of them found themselves floating down Rapid Creek, reaching out for branches on tree tops, trying to pull themselves out of the rushing water. Homes, lifted off their foundation, moved out on to Jackson Boulevard and ended up on Jackson Boulevard. People driving, thinking they could drive through the floodwaters. Their cars were washed away. It’s just amazing. And I’m so happy. You know, some people are saying that happened 50 years ago. Let’s move on. No, you can’t move on because it could happen again. And you know that it could happen again. All of the pieces to the perfect storm puzzle that occurred back on June 9th could occur again.”
Despite the possibility of another flood occurring, Riggio does think we are more prepared now than then. He says that back then collecting the data from data balloons, analyzing the data, plotting the data, and then displaying the information to the public was all done by hand. “Today, it’s computer, it’s all done by computer. And computers are so much faster and in many respects so much smarter, so that information can get out to the public a lot, a lot quicker. Plus it’s more accurate. It’s going to be more accurate and more refined. Back then, we just had this big broad area of heavy rain. Now with Doppler radar, which we didn’t have back then. Now, with Doppler radar, you can actually pinpoint within the line of showers where the heavy rain is occurring. And you could focus in on that with your warnings and be more precise with your warnings. Back then, we couldn’t do that.”
In Part 2, Riggio talks about the three things needed to produce the type of storm that occurred on June 9, 1972.
He explains, “Well, to get rain for a rain shower to develop, you need three things. You need moisture. And my gosh, we had moisture back then, copious amount of moisture. And we need instability. You need cold air over warm air. And we had that. We had a pocket of cold air aloft and and warm air near the surface. We had the instability. And you need a trigger. You need something to kick it off. And we had that we had a surface trough. And that was the trigger for that event.” Riggio continues explaining that often times when we see rain showers, the storm may develop over the Black Hills but then the winds typically push the storm off of the hills and out to the prairie. “We didn’t have that ability on June 9th,1972, the winds aloft, the steering winds were not there to push these thunderstorms off the Black Hills.”
Continuing Riggio explains, “So we have this copious amount of moisture. This a low level jet coming in from the southeast and that’s something else…usually at sunset that begins to weaken, that begins to lessen the input of moisture into these storms. Not on June 9. This thing stayed up 40 miles an hour. 40 miles per hour throughout after sunset, around even up to midnight, 40 mile per hour winds pumping in this copious amount of moisture from the southeast. And the storm just sat there. There was no winds aloft to push them off the Black Hills. The Black Hills weren’t about to move, so they just sat there and produced 100% of that moisture. 100% of that moisture coming in turned into rain on the ground. 100%. And again, another a rare happening.”
There was a historic amount of moisture in the atmosphere that moved into the Black Hills throughout the afternoon and evening hours on June 9. The amount of rain recorded was approximately 16 inches which is equivalent to an entire year’s worth of rain. Riggio says, “Near Johnson Siding, they recorded somewhere like six inches an hour. Radar recorded six inches an hour of rain near Johnson Siding. But that’s that’s again that’s historic. We didn’t see it prior to June 9th and we haven’t seen it since June 9th but it can happen again. It certainly can happen again.”
Beckman points out, “I mean you get an inch an hour up here and that causes problems. You get flash flooding from an inch an hour back in 2018-2019. My first year here I just remember how much water we got that year. We’re starting to see a little bit of greenery this year, too. And I saw some of these thunderstorms that would develop over the northern Black Hills or you had the water that washed out one of the bridges in Sturgis about a year or two ago and that’s a lot of water. And then I go back and I see how that compares to the ’72 flood. We’re not even in the same universe.”