From TheDenverChannel.com (Cory Reppenhagen):
Desert dust is littering Colorado’s trademark white powder snow and having a big impact on the spring runoff.
“It’s a big problem that many people don’t realize,” said Jeff Derry, the director of the Center for Snow and Avalanche Studies.
Scientists like Derry call it a “dust on snow” event.
They typically occur in the spring when storms pull dust out of the desert southwest and spread it out over the Colorado mountains.
Record winds from a storm back in February blew in loads of desert dust. It’s since been covered up with more snow.
“Eventually that dust layer will emerge to the surface of the snowpack,” said Derry.
Derry says the dust can advance when the snow completely melted by up to 50 days, which can rob a river of up to 5 percent of its annual runoff. That’s about a billion cubic meters of water for the Colorado River.
“When the water melts earlier, the plants become active earlier, and they use more water,” adds Derry.
Global warming plays a role in the process as well.
Scientists believe an increase in “dust on snow” events over the last decade may be the result of soil destabilization in the source region of Arizona and Utah. It’s not warm air temperature that speeds up the snowmelt, it’s the actual radiation from the sun that does the job.