Cooling trend dropping streamflows in Yampa River after mild month of March
April 8, 2015
Steamboat Springs — The Yampa River was still running at 163 percent of median flows Wednesday after dropping from 800 cubic feet per second April 3 to 606 cfs April 8, and it may go even lower before it rises again toward the peak of runoff.
Hydrologists working for the Colorado Basin River Forecast Center in Salt Lake City tentatively foresee the Yampa dropping as low as 340 cfs by April 17, but that shouldn't be taken as a sign that the river has prematurely peaked.
Snowpack in the Yampa Basin above Craig and Steamboat Springs is low, and temperatures have been atypically high since March, when the annual spring runoff began, but the Forecast Center still gives the Yampa a 90 percent chance of peaking at 2,000 cfs.
Paul Miller, a senior hydrologist at the forecast center, confirmed that Elkhead Creek in Moffat County saw its second highest total March streamflow volume in March.
Greg Smith, another senior hydrologist at the forecast center, said this week that annual streamflow peaks, especially on rivers in Colorado, tend to be driven by the melting of high elevation snow, and that has not happened yet.
"The immediate drop off (this week) is due to cool weather and also, low elevation snow is running out," Smith said. "In our models, we divide the basin into three elevation zones, and in a lot of the upper Colorado (basin) and in the whole area, the lower elevations (have melted) out in many places. The mid-elevation in some areas is nearly running out."
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Smith said he and his colleagues at the Forecast Center continue to expect the higher mountain peaks to contribute to the peak runoff in rivers like the Yampa this spring. He added, however, that as mild weather continues to chip away at the snowpack, it's very possible that current forecasts — which rate the chance of the Yampa in Steamboat reaching 2,000 cfs at 90 percent, 2,200 cfs at 75 percent and 2500 cfs at 50 percent — will be revised downward.
In the short term, the Yampa River Valley is in store for a modest amount of cold precipitation this weekend. Steamboat-based meteorologist Mike Weissbluth of the SnowAlarm blog said in an e-mail this week that the storm that brought two feet of desperately-needed snow to the Sierra's this week would arrive at the Steamboat Ski Area Wednesday evening with the potential of 1-4 inches of snow in time for the morning ski report and a chance for another inch or two during the morning hours.
However, the main energy from the storm was expected to stay to the north of Steamboat where the air is the most unstable and "upward forcing" is strongest, Weissbluth said.