Monday, March 20, 2017
Steamboat Springs The unseasonably warm weather in Routt County triggered record-setting flows March 18 through 20 in the Elk River at its confluence with the Yampa River west of Steamboat Springs, far surpassing the prior record for the date and causing a federal hydrologist who keeps a close watch on this portion of the Colorado River system to describe them as “shocking.”
“It’s crazy how high the flows are for this time of year,” Ashley Nielson, a senior hydrologist with the Colorado Basin River Forecast Center in Salt Lake City Utah, said. “I think we’re getting snowmelt at low and middle elevation and not at the higher elevations. But this is not something we expect this time of year.”
The Elk is still well below flood stage, but the acceleration of snowmelt during a time when snowpack is typically increasing stands out from the norm.
Flows in the river, which has its headwaters in the Mount Zirkel Wilderness Area northeast of Clark, hit a 24-hour peak of 1,050 cubic feet per second at 1:45 a.m. March 20, nearly doubling the previous record for the date, according to the U.S. Geological Survey. The previous record was 524 cfs, recorded in 2007. The median March 20 flow is 160 cfs.
At the same time, the Yampa River was flowing through downtown Steamboat Springs at a rate of 408 cfs, well above the median of 150 cfs (in the 90th percentile range for the date), but significantly lower than the 1916 record for the date of 690 cfs.
High flows in the Elk have been driven by snow melting under bright skies and daytime temperatures in the 60s, which have dominated the weather throughout the month. The National Weather Service reports the high temperature in Steamboat reached 70 degrees March 19, but a cooling trend is on the way.
The Elk had calmed down to 896 cfs as of 9:30 a.m. Monday as it went through its diurnal cycle of rising and falling flow volumes. However, the River Forecast Center foresees the river will continue to rise to more than 1,000 cfs through March 23, when a cooling trend calms things down March 25 through 31 and the river could remain above 600 cfs.
A pair of snowpack measurement sites operated by the Natural Resources Conservation Service confirm the record flows in the Elk are attributable to snowmelt above 9,000 feet, Nielson agreed.
The Lost Dog site, at 9,320 feet of elevation on the edge of the Zirkel Wilderness, has lost 3 inches of snow water equivalent since March 16, leaving it at 113 percent of median for the date. The Elk River measuring site, at 8,700 feet, has also lost 3 inches of snow water equivalent in the same timeframe, and snowpack there stands at 93 percent of median.
Nielson pointed to the Tower measuring site on the summit of Buffalo Pass northeast of Steamboat Springs as evidence that snowmelt has not begun at the highest elevations in the Park Range. The water content of the snowpack there, at 10,500 feet, has not changed more than a fraction of an inch since March 7.