River runners who run Warm Springs Rapid in Yampa Canyon next year might want to give the rapid a second look while scouting. In early August, rockfall altered the landmark drop significantly.
“It was a pretty dynamic event,” says local Hugh Newton, who hiked into the rapid in September to see the debris. “It should be pretty interesting to see next spring.”
Rated Class III-IV, Warm Springs typically is the crux rapid on the 72-mile trip from Deer Lodge Park to Split Mountain through the heart of Dinosaur National Monument. Two features stand out at various water flows: a wave called Godzilla about halfway down and a massive hydraulic called Maytag at the rapid’s bottom. At most flows, paddlers can pull right to miss them. Most who have seen it since the rockfall agree floaters will be forced to run the rapid down the center.
“The new fall of sandstone inhibits the usual path to quite a degree,” says Erik Feeley, a Yampa veteran who also hiked in to see it this fall. “Some rubble could get washed down this spring, but there are a couple of big, sharp rocks right in the middle that will likely remain for years to come.”
The change was first noticed by Chris Dachs and Peter Williams, of Dinosaur National Monument, on Aug. 3 during a low-water inflatable kayak trip down the canyon. When they arrived at Warm Springs, they “discovered substantial changes in the rapid’s geography.”
From the devastation — including randomly strewn new boulders, three distinct impact craters, shattered box elders with branches angled uphill and tree trunks coated with dried mud 12 feet high on the sides facing the river — they surmised that the change occurred from rockfall on river left, just downstream form the “coke bottle” scar responsible for the rapid’s formation in 1965.
Feeley’s theory is that the rock slab fell in two stages. The first — a triangular section from the lower part of the new cliff scar — dammed the river, creating a 15-foot-diameter crater and massive pool that filled with mud. A second rockfall then fell into this, resulting in the mud-caked trees, existing rocks and other debris.
However it came down, it likely will affect passage. The majority of the rubble is piled on river-right, just downstream of where rowers typically make their move to cut through the rapid’s top lateral waves. “It looks like it will confine your entry, especially at lower flows, eliminating the sneak line on the right,” Feeley says. “Even if next spring’s high water rearranges these boulders, they’ll likely provide a new hazard to making this crucial move. A new era through Warm Springs now exists. Impassible? We shall see.”