Photo Credit: Tight Line Media
It didn't just rain. It poured. For hours. And those hours were unusually warm, dumping massive amounts of spring moisture on top of melting winter snowpack. Storm conditions for the perfect disaster hovered over the Greater Yellowstone Ecosystem in June 2022 and the brunt of it convened in the unregulated, wild watershed of Yellowstone National Park.
“Due to record flooding events in the park and more precipitation in the forecast, we have made the decision to close Yellowstone to all inbound visitation,” said Cam Sholly, Yellowstone National Park superintendent on the day flooding erupted. “We have multiple road and bridge failures, mudslides and other issues.”
Jeff Dillon, a retired Idaho biologist, watched the flood fiasco unfold along with the rest of the country. It was humanity at Mother Nature’s mercy as highways crumbled, buildings sunk and people evacuated. During the peak of the park’s wash away, panic ruled then the water dropped and worry set in.
“There’s a lot of clean up and a lot hand wringing over the impacts to fish,” says Dillon, a fisheries biologist for 32 years at Idaho Department of Fish and Game. “But fish are resilient. Fish make a lot of babies for a reason. From a biological perspective, they’re going to rebound.”
He says that with confidence, the kind of confidence earned with experience. Dillon was the Upper Snake Region’s fisheries biologist during the Snake River flood of 1997. He witnessed, and worked through, the torrential mess that soaked its way across East Idaho nearly three decades ago with catastrophic chaos similar to Yellowstone in 2022. Both floods happened in June. Both floods flirted with epic volume, surging from well under 20,000 cubic feet per second (cfs) to nearly 50,000 cfs. But unlike undammed Yellowstone, there are dams in East Idaho that helped hold back some of the flow. Not much, but some. Despite that, damage took a severe toll in both cases.
“When you look at the river as it’s taking roads and dragging trees, it looks awful,” Dillon says. “Problem is people build too close when it’s controlled and then it turns uncontrolled so when the flows subside it looks stark. Trees tipped over. Side channels high and dry. The South Fork looked scarred. It looked like something bad had happened out there.”
And it had for us, but not necessarily for the wild. Fish were in the watershed long before us, and long before dams. Fish evolved with flood. Flood is part of the planet’s natural cycle, a necessity in many cases for proper function. When that cycle spins into drowning, we might not know what to do, but the fish do and Dillon has proof.
He had trackable tags in several dozen fish on the South Fork in 1997. It was the department’s first attempt to study the impact of non-native rainbow trout on native cutthroat trout. He suspected bows were cutting in on cutties. Now we know they are, but back then the possibility was an unknown and it needed investigation. A team of researchers were studying fish movement in 1997. They were looking for species overlap in spawning beds when the flood happened.
“It was quite fascinating to see those fish weather the storm,” he says. “They just find a spot to get out of the worst of it and hunker down. When the flood passes they get on with their business. Water quality goes down. It’s turbid and trees and other stuff are floating down the river, but they were not displaced. When it came time to make spawning runs they made them.”
One of the oldest sites surveyed in the state for annual fish population counts is the South Fork. The fall survey of 1997 showed no noticeable difference in number of fish. And even though bugs (fish food) did experience substantial losses short term, the fish surveyed that year didn’t look hungry. They looked healthy.