GLENWOOD SPRINGS — Late-season snows that helped boost the high-country snowpack in April wasted little time in melting off with the warm May temperatures.
The Colorado River, as measured at gaging stations at Dotsero and in Glenwood Springs below the Roaring Fork River, appears to have already reached its peak spring runoff flow as of a week-and-a-half ago.
According to daily streamflow tracking on the U.S. Geological Survey Water Resources website, the Colorado just below the confluence with the Roaring Fork River reached its highest level so far this season on May 18, at 9,600 cubic feet per second (cfs), with a gage depth at that point of 7.2 feet.
Cooler weather at the start of last week dropped the river level to 4,600 cfs at that location on May 23. The warm Memorial Day weekend brought river levels back up to 8,800 cfs on Tuesday, but another cool spell had the Colorado flowing at about 7,300 on Wednesday, according to the USGS data.
Likewise, the Dotsero gaging station recorded a peak flow of 6,000 cfs on May 18, while the latest warming trend brought the Colorado River at that point up to just 5,000 cfs on Monday. By Wednesday, the reading at Dotsero was below 4,000 cfs.
Which could very mean that’s all she wrote for the peak runoff this season, said Aldis Strautins, a hydrologist with the National Weather Service in Grand Junction.
“The upper Colorado appears to be on a downward track after that peak back on May 18,” he said. “We still have a little bit of snow left to come off, so we’ll probably see it come back up with the next warming trend. But I don’t think we’ll see those same levels again.”
According to Mage Hultstrand, snow survey specialist for the Natural Resources Conservation Service in Denver, only about 22 percent of this year’s snowpack in the Colorado River Basin remains at this point.
This year’s snowpack topped out at just over 15 inches of snow-water equivalent in late April, Hultstrand said. As of Wednesday, the snow-water equivalent was down to about 4 inches, according to the latest SNOTEL snowpack summary.
Another warming trend forecast through this coming weekend could take care of what snowpack remains, at least in the Colorado Basin.
Meanwhile, the Roaring Fork River at Glenwood Springs reached a season high point on Monday of approximately 3,400 cfs, with a gage depth of 4.75 feet, according to the USGS streamflow data. That was higher than the May 18 reading of 3,000 cfs, when the Colorado was peaking.
According to the Roaring Fork Conservancy’s weekly streamflow report for May 23, transbasin diversions from the upper Frying Pan River to the Arkansas River Basin have impacted streamflows in the Roaring Fork. As of May 23, Ruedi Reservoir was just 67 percent full.
“The Roaring Fork Watershed is still experiencing a moderate drought,” according to the weekly Conservancy report.
“We still have a little bit of snow left to come off, so we’ll probably see it come back up with the next warming trend. But I don’t think we’ll see those same levels again.”
Hydrologist with the National Weather Service in Grand Junction