Steamboat Springs Rapid snowmelt overwhelmed culverts and damaged portions of Seedhouse Road in northern Routt County on Monday night, and a flood warning remains in effect for the Elk River near its confluence with the Yampa River in Milner.
Routt County Road and Bridge Director Paul Draper confirmed Tuesday that the force of the water caused the road to slough off in several places. However, he said the affected stretch of road between Elk River Guest Ranch and Vista Verde Guest Ranch remains passable for now.
Seedhouse Road leaves Routt County Road 129 (Elk River Road) just north of Clark, then roughly follows the Elk River.
Draper said the damage wasn't caused by a flooding creek or river, but instead by melting snow pouring off a slope above the road.
"The water flowed so ferociously it carved the bank off in a couple of places," Draper said.
The water flowing across the road was 6 to 8 inches deep about 9:30 p.m. Monday, Draper said.
In one location, where the river hugs a steep slope above and a steep slope that drops to the river below, the damaged section of the road was 20 feet wide and plunged 12 to 14 feet straight down. The soils beneath the road shoulder had become saturated, Draper said.
Draper said the damaged road surface consists of two layers of chip and seal on top of a gravel base. County bridges are built to withstand 100-year floods, but culverts on rural roads are built to tolerate only 20-year floods. It's clear that Routt County is experiencing something beyond a 20-year event, Draper observed.
As of midday Tuesday, the damage done to the road would take about a week to repair, he said.
Closer to Steamboat Springs, Colorado Department of Transportation crews were keeping a close watch on the U.S. Highway 40 bridge that crosses the east fork of the Elk River just above its confluence with the Yampa River.
CDOT spokesman Bob Wilson confirmed that crews used heavy equipment Tuesday morning to pull logs and other flood debris away form the bridge supports. They did the same where the highway crosses Elkhead Creek east of Craig, he said.
Those measures are taken to keep the debris from backing up the river and compounding flooding and to protect the bridge. CDOT officials want to keep the river from flowing over the highway if possible, because in extreme cases that can lead to the road washing out, Wilson said.
CDOT crews will monitor the bridge daily as long as the river is high.
The National Weather Service in Grand Junction has issued a flood warning until late Thursday for the confluence of the Elk River with the Yampa River at U.S. Highway 40 about seven miles west of Steamboat Springs. Flood stage on the Elk River at the confluence is 7 feet. As of 7:15 a.m. Tuesday, the river was at 7.5 feet. The river had receded to 7.08 feet by 3:15 p.m., but was expected to rise to 7.8 feet by 6 a.m. today.
According to the warning, homes near the confluence will be threatened by the flooding. On Tuesday afternoon, floodwaters had encroached on homes off Routt County Road 44 near the confluence of the Elk and Yampa rivers.