The National Weather Service extended a flood advisory to the northern Front Range for the first time this season Sunday, as warm temperatures accelerated the melt of high-country snowpack.
The potential for record flooding is a big concern across much of the state, the Weather Service said.
Forecasters stressed that the rivers are running not only deep but also fast and cold.
“Persons with interests along these rivers and creeks are urged to use extreme caution,” the agency warned. “Stay clear of riverbanks that could become very unstable due to the high stream flows.”
Authorities have been watching rivers in northwest Colorado approach or spill beyond their banks since early last week.
The runoff started to affect rivers in Larimer and Weld counties Sunday, prompting a flood advisory there until 3 p.m. Wednesday.
Minor flooding was forecast for Lari mer County, including the Laramie, Cache La Poudre and Big Thompson rivers.
Flows are expected to increase through Tuesday.
The Big Thompson River could spill over into parking lots and trails in Estes Park late today into early Tuesday, forecasters said.
The Cache La Poudre could rise enough to close streets in Fort Collins and Greeley.
A flood advisory is in effect until at least 11:45 a.m. Wednesday for much of western Colorado, including Summit County.
Among the areas of concern are Tenmile Creek near Frisco, the Blue River upstream and downstream of Dillon Reservoir and Hamilton Creek on the north side of Silverthorne.
In Grand County, authorities are watching the Colorado River, Muddy Creek, Troublesome Creek and Willow Creek, which all were at or above their banks Sunday.
Campgrounds along the Colorado River reported minor flooding. Willow Creek at Colorado 125 in Jackson County was approaching the bridge level Sunday.
The Elk River at Milner was just short of its 7.5-foot flood stage Sunday afternoon, and the Yampa River has held steady at 6.5 feet since Thursday, about a foot below flood stage, according to U.S. Geological Survey river gauges.
Metro-area waterways have shown no signs of flooding yet. Clear Creek in Golden and Cherry Creek in Denver were rated “normal,” and each was flowing at little more than half of its flood stage, according to the U.S. Geological Survey.
Joey Bunch: 303-954-1174 or jbunch@denverpost.com
