Spring runoff is well under way
March 29, 2012
Steamboat Springs — The light drizzle that briefly kissed Steamboat Springs on Thursday morning marked the first moisture to fall on the city since March 19 and 20, when 1.8 inches of snow fell in a two-day span. But Thursday's 0.02 inches of moisture wasn't enough to obscure the fact that the water stored in the mountains surrounding the Yampa Valley has begun to decline at a time when it still should be increasing.
Aldis Strautins, a hydrologist with the National Weather Service in Grand Junction, said Thursday there are signs that snowpack in the Upper Yampa River Basin already has peaked for the season.
"When I look at the graph of the Yampa above Maybell, which includes the Little Snake (River), the (snowpack) measuring sites are at or below 2002 levels," Strautins said. "It looks like we've hit that crest and are on the downward side of snow accumulation. I'm seeing that things look pretty dry."
Compounding the outlook for spring and summer runoff is the three-month outlook for above-average temperatures and below-average precipitation, he added.
Few people who irrigate, fish for trout, paddle a kayak or plop on inner tubes for a lazy float down the Yampa have forgotten summer 2002. That was the year when drought conditions led to wildfires in the Flat Tops, Sarvis Creek and Mount Zirkel wilderness areas on all sides of Steamboat. It also was the summer when the Yampa was ankle deep in mid-July and Colorado Parks and Wildlife officials called for a voluntary ban on fishing to save the stressed trout population.
U.S. Geological Survey records show that the Yampa River where it passes under Fifth Street first fell below 30 cubic feet per second on July 12, 2002, and fell below 20 cfs on July 15 before beginning a dramatic reversal, climbing to a healthier 90 cfs by July 27. The reprieve came in the form of natural rainfall and calls for water from senior rights holders downstream from Steamboat.
On Thursday afternoon, the Yampa was flowing at 448 cfs at Fifth Street, well above its average of 200 cfs for the date. It was a sign that spring runoff is well under way at low elevations.
The Natural Resources Conservation Service reported Thursday that the snowpack in the combined Yampa and White river drainages stands at 57 percent of average.
Closer to home on the west summit of Rabbit Ears Pass, however, an NRCS snotel measuring site indicates the 12.8 inches of water stored in the snow is just 48 percent of the average 26.7 inches. And a forecast for Saturday that calls for temperatures in the valley to surpass 70 degrees suggests the number will go lower before a chance of rain and snow returns to the Park Range on Sunday.
Perhaps of even more concern is that the average peak snowpack on the west summit — snowpack refers to water content stored in the snow, not raw snow depth — is 30.2 inches of water and the average peak date is April 24.
NRCS records show that in the last seven days the west summit of Rabbit Ears lost 1.1 inches of water content.
The current trend is in stark contrast to the late spring and early summer 2011, when the west summit still held 5 inches of snow water equivalent on June 23.
And the downward trend is also evident at 10,400 feet on Buffalo Pass at the Tower measuring site. The 28.5 inches of water there is 63 percent of average. And snow depth on Buffalo Pass had dropped from 82 inches on March 22 to 74 inches on Thursday.
However, Jay Gallagher, manager of the Mount Werner and Water Sanitation District, which draws the majority of the city's domestic water from Fish Creek Reservoir in the Buffalo Pass drainage, said the reservoir already is assured of filling this spring. Fish Creek Reservoir is 74 percent full, and even when accounting for evaporation and seepage into the soil, the 28.5 inches of water stored on Buffalo Pass represents three times the amount needed to fill the reservoir.
The concern later in the summer may be conserving water on peak demand days, Gallagher said.
The average peak water content for the Tower site on Buffalo Pass is 52.4 inches, and at least according to the calendar, there's significant time remaining before the average peak date of May 6.
But Strautins, of the National Weather Service, warns that the die for the water season might already be cast, and the Upper Yampa Valley could be in for a relatively hot, dry summer.
To reach Tom Ross, call 970-871-4205 or email tross@SteamboatToday.com