A massive debris flow triggered by flash floods that followed a wildfire in Northern California is believed to have killed scores of fish along a 50-mile stretch of the Klamath River last week.

Intense storms sent floodwaters coursing through an area recently burned by the McKinney fire, pushing charred soil, rocks and trees into the river near Humbug Creek, said Craig Tucker, natural resources policy consultant for the Karuk Tribe. At least four deaths have been linked to the 60,000-acre fire, which is the largest to burn in California so far this year.

The debris flow was reported after up to three inches of rain fell on the east side of the fire Tuesday, Aug. 2, said Mike Lindbery, a public information officer on the fire.

A remote gauging system managed by the Karuk about 20 miles downstream, at Seiad Creek, found that the dissolved oxygen in the river plummeted to zero for about four hours Wednesday night, then again the following night, Tucker said. Dead fish started washing up farther downstream in Happy Camp that Thursday.

“It’s like dead bodies are floating to us out of the smoke,” he said.

Active fires — which include both the McKinney fire and the 8,000-acre Yeti fire — have precluded a full investigation, as virtually everything upstream of Happy Camp remains evacuated, Tucker said. But it seems likely the fish kill extended along 50 miles of river, he said.

“From about Humbug Creek all the way to Indian Creek, which is in Happy Camp, it was a kill zone those two days,” Tucker said. “It looks like probably everything in the river died.”

Species include juvenile chinook and coho salmon, as well as trout, Pacific lamprey, suckers, crayfish and various macroinvertebrates, he said.