The skies have cleared up over the Western Slope lately, but a lot of snow fell on Colorado. That's good news for water supplies, but that might change, depending on how the desert storms hit in the spring.
In the North Fork Valley, Amber Kleinman and Marla Bishop both posted photos to iSeeChange of deep snow covering everything. The Colorado Snow Survey Program show that Colorado’s mountains are at 112% of normal. It’s a lot to shovel, but it’s not a record-setter. According to the National Weather Service, over the past 31 years, this winter is currently in 10th place.
The snow is good news, though. Last year was exceptionally dry. For a lot of people, it’s not winter’s snow up there, its summer’s water. That’ll help with the drought but there is a danger it could be too much of a good thing.
“With a large water supply in the mountain snowpack, accelerating those melt rates can cause the rivers to rise very, very rapidly,” says Thomas Painter. He’s a research scientist with NASA’s Jet Propulsion Laboratory. His big thing? Dust.
Every year, dust blows from the deserts of Nevada and Utah. It lands on the first thing it hits: the Rocky Mountains.
“The particles are big enough that they don’t percolate down from the surface. They remain blocked there. As they melt down, they pick up more and more dust layers that have come previously in the season. So the surface gets darker, and darker, and darker while the sun gets higher and higher. It’s a multiplicative effect on the snowmelt rates,” he says.
Dust is a huge variable on snowmelt rates. He says 90% of the energy it takes to melt snow comes from sunlight absorption, not temperature. Snow in the mountains doesn’t melt because summer is warmer, but because there’s more sunlight higher in the sky.
So, aside from the length of the ski season, what does this mean? It’s all about how fast the water melts. Last year was pretty dry, but one of the cleanest years. It was a stark difference from 2009.
“We call that the extreme dust year. That was the ‘Martian Spring’ because everything was so red and so heavy and the runoff came so quickly. Infrastructure was threatened and just capturing water and managing it was really tough.”
Not only can the deluge cause flooding, it also puts more water in the ground, earlier. In Colorado, this is a problem.
“In melting earlier,” says Painter “you’ve opened up the season that water is in the root system, so you have a longer growing season.”
More water gets used, and the amount available to us and everyone else that depends on the Colorado River Basin, drops. Also, dust’s impact is proportional to the amount of snow in the mountains. With the healthy snowpack we have, it may be more of a liability when the dust storms come.
It’s tough to say what will happen. They can look at how much dust is available to be picked up by the spring storms, “but in terms of the number of storms and those with the right trajectories to scour the deserts, that we don’t have yet,” Painter says, “if we did, we would be very wealthy.”
So, massive fortunes unrealized, everyone will have to wait and see how the spring’s dust will affect our snow and our water supply.