Runoff news: The National Weather Service has issued a flood advisory for parts of the Front Range

A picture named floodthreatcwcb06062011

From The Denver Post (Joey Bunch):

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 Larimer 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…

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.

From Denver Water (Stacy Chesney):

Recent Snotel measurements show record or near-record snowpack upstream of Dillon Reservoir. Forecasts call for peak inflows later this month to be in the range of 2,800–4,100 cubic feet per second, or cfs (average this time of year is about 1,700 cfs, and the record peak, set in 1995, is 3,408 cfs).

As in years past, Denver Water’s goal is to operate the reservoir so the peak outflow does not exceed 1,800 cfs, which is approximately the “bank full” condition for the Blue River downstream of the dam. Because of this year’s exceptionally high snowpack and the uncertainty of the amount, timing and rate of the melt, it may not be possible to keep the peak outflow below 1,800 cfs.

Denver Water is continually monitoring conditions and took a number of precautions — including lowering Dillon Reservoir levels — earlier this spring in anticipation of the coming snowmelt. The utility can only lower the reservoir so much, but intends to operate its system consistent with the outflow goal, while also fulfilling its legal and service-related obligations.

Denver Water will continue to monitor conditions and provide updates as they become available; however, residents and businesses along the Blue River downstream of Dillon Dam should be prepared for flows in excess of 1,800 cfs in the upcoming months. Currently, the outflow is 1,300 cfs and Denver Water likely will increase outflow to 1,400 cfs this afternoon and through the weekend. The current inflow to Dillon Reservoir is about 1,600 cfs.

From the Fort Collins Coloradoan (Trevor Hughes):

The “hydrologic advisory” applies to Larimer County and west-central Weld County, and warns that low-lying areas along rivers and streams will experience rising water levels in the early part of the week. The advisory runs to 3 p.m. Wednesday.

“Minor flooding of low-lying areas can be expected along the Laramie and Cache la Poudre rivers as snowmelt and stream flows increase through Tuesday,” the weather service said. “The Big Thompson River through Estes Park is also forecast to rise. By late Monday night into early Tuesday morning, flows may become high enough to produce minor flooding into parking lots and walkways along the Big Thompson River in Estes Park.”

The service says Weld County may see the Poudre River rise 6 to 12 inches, which would be high enough to close 71st Avenue over the Poudre on the northwest side of Greeley. The Poudre River Trail in Greeley has been closed between 47th Avenue and 83rd Avenue, due to high water…

Since June 1, the Poudre River in Fort Collins has risen from 900 cubic feet per second, or cfs, to about 2,500 cfs this morning.

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