Tenmile Creek and Straight Creek approach flood stage as spring runoff lets loose

A weathered cross signifies the 9,418-foot summit of Green Mountain, Summit County’s 100th-highest point, on Tuesday evening, with the Gore Range in view at right, Ute Peak in view at left and Green Mountain Reservoir in view down below. The reservoir, which was drastically low just a month ago, is filling up quickly as streamflows on the Blue River below Dillon Dam have spiked to 705 cubic-feet-per-second (cfs) due to fast-melting snowpack, according to the U.S. Geological Survey, as of Thursday afternoon. Stream flows on the Blue below the Green Mountain Reservoir dam were up to 791 cfs.
Antonio Olivero / aolivero@summitdaily.com

FRISCO — The water is roaring across Summit County. Tenmile Creek, Straight Creek and the Snake River are all approaching flood levels as the great 2019 spring runoff rushes in with thunderstorms on the way this weekend.

After a cold, wet May, temperatures are finally rising in Summit, with highs in the 60s and lows in the 40s creating the conditions necessary for the snowpack to crack and crumble.

Tenmile Creek is one of the best gauges of how powerful the runoff is. The stream is currently cresting at 3.88 feet, with overflows into low-lying areas in and west of Frisco beginning at 4.8 feet.

At 5 feet, Tenmile Creek is at flood stage. At that point, there will be minor flooding of roads and properties along Tenmile Creek. At 6.5 feet, or moderate flood stage, houses begin to flood. Major flood stage starts at 7.5 feet, with significant flooding in Frisco and on the westbound lane of Interstate 70.

Residents should take some comfort in knowing that Tenmile Creek never has gone above 5.14 feet, a mark set June 17, 1995. Frisco authorities have continued to warn residents about potential flooding, with town and county staff on standby in case banks get run over.

The Snake River is currently sitting at 2.7 feet, with flood mitigation action called for at 3.3 feet. The Snake’s record crest was set June 6, 1972, when it reached 3.88 feet. At 3.8 feet, Keystone begins to flood, but that level has been reached only twice since record keeping began there in the 1940s.

Straight Creek in Dillon is currently at 4.86 feet, with action stage at 5.3 feet and flood stage at 6 feet. That stage never has been reached in recorded history, with Straight Creek topping out at 5.78 feet June 17, 1995.

Water flows into and out of local reservoirs also are rapidly speeding up. On Friday, June 14, Green Mountain Reservoir started ramping up outflows into the Blue River. Starting at 800 cubic feet per second, the reservoir will increase flows by 50 cfs every two hours until it reaches 1,400 cfs at 4 a.m. Saturday. That flow will be maintained until further notice.

The increased flows are meant to support the Coordinated Reservoir Operations initiative which seeks to enhance spring water flows consistent with the Upper Colorado River Endangered Fish Recovery Program. The conservation program seeks to boost the number of humpack chub, razorback sucker, bonytail and Colorado pikeminnow populations in the Blue.

Further south, the Dillon Reservoir is rapidly filling up after space was made for runoff these past few weeks. Water is dumping into the reservoir at a rate of more than 2,100 cfs, with outflows into the Blue River under the dam reaching up to 700 cfs. The reservoir is currently 83% full and just 15 feet shy of reaching peak elevation.

As far as weather, the weekend is looking to bring a few more showers in the area. Saturday will see possible thunderstorms in the morning with scattered showers throughout the evening. Sunday will see scattered thunderstorms through the day, with light rain possible again in the evening.

via:: Summit Daily