Storms that dumped more than 13 feet of snow on Summit and Grand county ski areas also left behind a much needed gift: water.
December 2016 and January 2017 tied a record for the highest snow water equivalent in the part of the Colorado River Basin where Denver Water collects its snow.
The snow water equivalent, or SWE, is a complex but critical piece of information for water planners. In simple terms, it’s the depth of water that would cover the ground if all the snow melted.
“Coloradans are familiar with hearing about snowpack levels, but the snow water equivalent is perhaps even more important,” said Nathan Elder, senior water resource engineer.
In December and January, the SWE in Denver Water’s Colorado River Basin watershed came in at 10.2 inches of water — the highest combined SWE accumulation for those two months since December 1980 and January 1981.
“Knowing the snow water equivalent in the snowpack helps us estimate how much water will flow into our reservoirs when the snow melts in the spring,” Elder said.
Denver Water relies on automated SNOTEL weather stations and monthly manual measurements to get accurate assessments of the amount of moisture packed into the snow.
Dillon Reservoir caretakers Rick Geise and Donald McCreer strapped on their snowshoes to measure snow near the top of Shrine Pass in Summit County on Jan. 30, 2017. It’s one of 11 locations in Grand, Park and Summit counties where Denver Water crews collect samples on snow-measuring courses. (Check out “Why Denver Water loves snow” to see our crews in Grand County measure snow at the base of Berthoud Pass in 2016.)
“The fall was warm and dry, but since Thanksgiving, it’s been snowing like crazy,” Geise said. “We run the courses at the end of the winter months to get a first-hand look at what’s really on the ground.”
Capturing snow samples looks like spear-fishing. Crews jab a specially designed hollow pole into the snow until it hits the ground. The pole measures the snow depth and captures a sample that’s used to determine water content.
“Ski areas love that champagne powder, but we like to see snow with lots of water inside,” Geise said.
Snow water equivalent is one of many pieces of information Denver Water uses to determine the amount of water available to fill reservoirs and supply customer needs. Snow provides 80 percent of Denver’s water supply; rain provides the rest.
Snowpack in Denver Water’s Colorado and South Platte River watersheds stood at 135 percent and 124 percent of normal, respectively, as of Jan. 31.
The snowpack is in good shape for this time of year, Elder said, but the normally snowy months of March and April are still ahead. “We often see ups and downs throughout the winter,” he said. “We’re hopeful the snow keeps coming.”