GLENWOOD SPRINGS — For longtime locals, the final day on the Vail Mountain ski slopes is a customary ritual, the last chance to make use of the nearby network of chairlifts and cruise spring snow before the so-called “mud season” transition to summer.
While the mountain attracted its fair share of disciples on the Easter Sunday closing last weekend, some of the region’s most dedicated skiers went the opposite direction, recognizing that the best snow to be found was already in the Colorado River.
“The brown frown is bringing me down,” said Mike Wertz, a 23-year resident of Vail whose ski days regularly approach triple digits. “I’d much rather be doing this.”
Despite above-average snowpack on his home hill, Wertz had joined a throng of stand-up paddle (SUP) surfers and kayakers making the most of an unseasonably early spike in the spring runoff at the Glenwood Springs Whitewater Park. Mud season, it seems, has turned to dust season, and impacts of the gritty layers of dirt covering the mountain snowpack — Wertz’s “brown frown” — have been revealed twice over: both as bad skiing conditions and increasingly early runoff.
Make no mistake, the dust-on-snow phenomenon is real. And it’s making a mess of things in the Colorado Rockies.
During recent years, desert dust carried by strong winds has been settling thick and dark on the snowpack in the Rocky Mountain headwaters of the Colorado River. Snow dusted with dark particles absorbs more of the sun’s rays and melts faster than clean snow. According to researchers at the National Oceanic and Atmospheric Administration’s Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado in Boulder, the snowpack is melting out some six weeks earlier than it did in the 1800s. And the problem appears to be getting worse.
It’s not an issue to be underestimated. Studies dating to the moderately dusty years of 2005-08 show that the dusty snowpack robbed the Colorado River of 5 percent of its flow before it reaches the Grand Canyon, equating to about 750,000 acre-feet annually, or about twice what the city of Denver uses. During 2009, 2010 and 2013, scientists observed unprecedented amounts of desert dust falling on Colorado snowpacks, about five times more than observed from 2005-08.
Those extra layers of dirt resulted in an extra percentage point of water loss as snowmelt creeps earlier into the spring, and less water is left for later in the year. Never mind the future exacerbation of climate change models. It’s a phenomenon that already has been observed this spring as the Colorado River surged to more than 8,000 cubic feet per second (cfs) in Glenwood and 14,000 cfs at the Utah state line last week.
“The surging being logged on streams throughout the Colorado mountains is likely to be sustained until at least (this past) weekend,” reported Chris Landry, who heads up the Colorado Dust-on-Snow program as director of the Silverton-based Center for Snow and Avalanche Studies. “Several watersheds experienced flows (Tuesday) that approached their median peak flow levels.”
In other words, the water is rising, and fast. Landry only capped the stream surge this weekend because of a forecast for more snow that should temporarily cover the dust — and potentially add to it.
The thing is, dust doesn’t melt. It merely grows darker and more concentrated as the snow beneath it melts, exponentially increasing the rate of runoff as the sun’s intensity grows with the approach of summer.
The research suggests that we can keep the snow on our mountains longer if we can figure out a way to adopt dust-reducing land management strategies and rehabilitate major dust sources in the Southwest. Meanwhile, we are forced to adapt.
“In the Upper Colorado River Basin, the snowpack is our most important reservoir,” said dust-on-snow research pioneer Thomas Painter of NASA’s Jet Propulsion Laboratory. “With continued dusty years and greater warming, water managers will have to make their decisions very early in the season. No longer will they have the nice long snowmelt season, shortened as it already has been, to see how snowmelt runoff is going.”
And neither, apparently, will the skiers and river runners.
Scott Willoughby: swilloughby@denverpost.com or twitter.com/willoughbydp
