Avalanche debris adds new variable as Frisco monitors surging flow of Tenmile Creek

Ten Mile Creek & Ten Mile Canyon, Frisco, Colorado
Todd Powell

The town of Frisco is asking residents to be proactive in preparing for potential flooding this spring following prolific snowfall this winter.

While town representatives say they aren’t more concerned with the runoff this season than in years past, a number of avalanches in the area this winter has created new variables as the town begins efforts to monitor water flows in the Tenmile Creek.

“There are so many factors that have to come together to create a snowmelt that has the potential to flood Tenmile Creek,” said Vanessa Agee, Frisco’s marketing and communications director. “It’s been cold at night, and since May 15 the CFS (cubic feet per second) in the creek has actually gone down each day. The thing that’s changed is we know there’s a lot of debris in the creek. Public works has been going out twice a day to check on the creek, and they’re already picking up debris.”

It’s no secret that Colorado enjoyed a big snow year this winter, and well into the spring. Todd Dankers, a forecaster with the National Weather Service in Boulder, said that the county currently has a snowpack at about 150% of average. However, as long as the weather cooperates, officials aren’t overly concerned about rapid melt off.

“So far to this point these cold temperatures have helped,” said Dankers. “The other thing is it’s still dropping below freezing at night. So it’s extending the melt off, bringing out a little water every afternoon and resetting at night. That helps to regulate it over time. We’re in a pretty good situation for avoiding problems, despite the amount of water sitting on the ground.”

Dankers continued to say that while temperatures are expected to rise somewhat this weekend, the forecast for next week calls for highs in the 40s and 50s, with below freezing temperatures at night.

The Tenmile Creek is currently sitting at about 2.43 feet and about 123 CFS, well below flood stage that kicks in at five feet, according to the U.S. Geological Survey stream gauge. Agee said that Frisco hasn’t seen significant flooding since 1995, when the snowpack was upwards of 180 percent of average. So while runoff isn’t a major concern for now, assuming there’s no rapid increases in temperature or a major rainstorm, avalanche debris has added another factor for concern.

The fear is that debris from avalanches in the waterway could create small dams at the town’s bridges over the creek — there are four in total — which could potentially block the water flow, break and create sudden and substantial increases in flow. Frisco has already begun monitoring for such an event.

Frisco public works director Jeff Goble said along with closely monitoring the water flow on the creek, his team is also taking two trips a day out to the town’s bridges to check for debris build-up or obstructions in the creek. So far, the town has already pulled out debris from two sites — mostly sticks and small obstructions.

Goble said the town is using a modified backhoe with an attached thumb — a device similar to a lobster claw that attaches to the machine — to clear out the debris. Goble also noted that he has alerts set up so the town will know if water levels rise to near flood levels, or if there’s a sudden drop in flow that could be a sign of upstream obstructions.

“We’re keeping a close eye on it so we’re ready to go should anything happen,” said Goble. “We’re doing everything we can short of going out to the avalanche chutes and cleaning them out, which is an impossibility.”

While the town keeps an eye on the creek, there’s also plenty of ways that residents along the Tenmile Creek can be proactive in preparing for the worst. The town is offering sandbags at the Town of Frisco Public Works facility, located at 102 School Road, from 8 a.m. to 4 p.m. Monday through Friday. The first 100 sandbags per lot (not by address) are free, while any subsequent sandbags are $0.25.

The town is asking residents to fill their own sandbags from one of three sand piles located at the N. 6th Avenue cul-de-sac north of Galena Street, the public works facility and the intersection of Madison Avenue and Sunset Drive. Once residents are finished with the bags, the sand should be dumped back into one of the piles, and the bags can be disposed of or repurposed.

Additionally, the town is asking anyone who observes any obstruction issues on Tenmile Creek to contact the Frisco Public Works Department at 970-668-0836. Residents can also reach out to assistant community development director Bob Gibson for help in determining if their property is in a special flood hazard area at 970-668-5276 or at BillG@townoffrisco.com.

On top of Frisco’s efforts, Summit County also offers a comprehensive flood preparedness guide that includes resources for all the town and areas in the county. The guide can be found at SummitCountyCo.gov/flood.

“We want people to know that we’re thinking about it, and that we’re paying attention,” said Agee. “We’re inspecting the creek twice a day, but it’s always helpful to have people living along the creek alerting us as well. If folks see something, we want them to call public works, or 911 if it looks like an emergency.”

via:: Summit Daily