The whiter the snow the longer it stays around. Just one more reason to be concerned with air pollution.
Fast-melting sooty snow may have impact on state’s water supply. At
The concern is this: Pollution from the Central Valley, Bay Area or
Did you know? The average snow crystal contains thousands of particles, including soot and dust. The more soot and dust, the darker the crystal. And the darker the crystal, the faster it will melt when exposed to sunlight.
It might not be visible to the naked eye, but those particles decrease the snow’s albedo, or its ability to reflect sunlight. Darker snow absorbs more heat and melts faster, exposing bare ground, which also accelerates melting. "It’s like placing tiny toaster ovens into the snowpack," Charlie Zender, a University of California, Irvine, associate professor of earth sciences, said in 2007 after concluding that one-third or more of Arctic warming can be attributed to sooty snow.
The most recent of the studies, released earlier this year by the U.S. Department of Energy’s Pacific Northwest National Laboratory, suggests changes in the brightness of the snow results in its melting two or three weeks earlier than pristine, white snow.
And that’s a problem for water managers, who depend on a slow and steady snow melt throughout the spring to store as much water as possible in
Other studies already have raised concerns about the Sierra snow melt diminishing earlier in the year because of climate change.
Invisible greenhouse gases may be a more significant factor than the dirty snow, Qian said. But another study, co-authored by the California Institute of Technology’s Jet Propulsion Laboratory, concluded that a decrease in local pollution could help alleviate the impact of climate change on snow melt patterns.
Almost everyone contributes to the problem. Soot comes from tailpipes, from factories or from power plants. Scientists say the new research gives the public ways to fight climate change now by decreasing the amount of pollution they generate directly or indirectly, such as how much they drive or how much energy they use.
On Wednesday, snow surveyors will trek into the
The good news, he said, is that soot is less likely to darken snow in portions of the Sierra that are heavily timbered. Researchers say they still need to learn more about how much soot is actually deposited in the mountains, as well as whether other particles, such as dust or ash, can cause earlier snow melt.