Since November, motorists passing through Glenwood Canyon have been greeted by a jarring scene: backhoes and excavators toiling in the Colorado River. The heavy machinery is there to remove 240,000 tons of debris left when flash flooding in July 2021 caused a rock flow to rush down the canyon’s walls, which had been burned bare by the Grizzly Creek fire a year earlier. The flood wrecked portions of I-70 and blocked the river with mud, sediment, and rock. The cost of mitigation will total $24.2 million, but the Colorado Department of Transportation predicts the road and the waterway will be cleared by early this month—just in time for the next flash flood season. With more impermeable soil and less vegetation because of the fire, even modest amounts of rain could lead to further damage in the canyon. “This summer,” says Paul Santi, a professor at Colorado School of Mines who has been studying debris flows since the 1980s, “I think there’s a chance we’re in for more of the same.” The good news? Mother Nature always renews herself. The bad news? In the interim, the view of heavy machinery working in the river could become an all too familiar sight.