#Snowpack #Runoff news: ~Average dust on snow season — 6 events

Click on a thumbnail graphic to view a gallery of snowpack data from the Natural Resources Conservation Service.

From The Denver Post (Jason Blevins):

The lack of dust — at least on Colorado’s central and northern mountains — removes one capricious ingredient from the always tricky formula of forecasting runoff.

“Many factors impact the timing and flow of spring runoff, including soil moisture, snowpack, weather, dust on snow and solar radiation. Given all the variables that play a role, we’d hesitate to say that the lack of dust makes it easier to predict runoff,” Denver Water spokeswoman Stacy Chesney said. “The lack of dust on snow benefits water managers because, all other variables held constant, it means a slower and more predictable melting of the snowpack.”

It takes careful coordination to fill all 19 of Denver Water’s reservoirs, a balancing act that weighs a range of inflows, water rights, customer demands and projects, all influenced by dust, weather, snowpack, soil moisture and sunshine. Sometimes, water managers release water to make room for a surge of snowmelt.

Strong snowpacks in the South Platte Basin in recent years, combined with increased conservation by Front Range users in 2014, meant Denver Water diverted the least amount of Western Slope water through the Roberts Tunnel beneath Dillon Reservoir since it opened in 1963. Last year, also one of very low dust, Denver Water diverted the second-least amount since the tunnel opened.

Snow researchers in southern Colorado for 13 years have studied the red dust swirled onto the snowpack from the Colorado Plateau.

The Colorado Dust on Snow Program was launched up Red Mountain Pass outside Silverton in 2003, where researchers with the Center for Snow and Avalanche Studies had started noting stronger dust storms laminating the San Juans in a pink patina of sun-sucking dust. When the spring sun began melting the snowpack, those dust layers would collapse on top of one another, creating a dark blanket that absorbed sunshine and hastened snowmelt from a slow trickle into a sudden surge.

By 2008, the dust-on-snow researchers were studying snowpacks atop a dozen Colorado mountain passes, compiling data that now are essential tools for water managers tasked with corralling as much of Colorado’s own water before it rushes downstream to other users.

They measured three dust storms the first year. There have been big years, with as many as 12 dust events: 2008-09 and 2011-12. And there were years with only three: 2003-04 and 2014-15.

This winter was about average, with six dust events and most of them relatively small. Most interesting this year was the lack of dust accumulation on Berthoud, Loveland and Rabbit Ears passes.

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