Utah Scientist: Dust Shortening Winters

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SALT LAKE CITY (AP) -- Western winters are getting shorter because of dust kicked up by urban and agricultural development, a University of Utah researcher said.

Thomas Painter, head of the school's Snow Optics Laboratory, said in a lecture at the downtown library Monday that disturbed particles from the Colorado Plateau mix with snow, limiting the heat it can reflect. As a result, today's snowpacks melt about a month earlier than they once did. Painter's research affirms longtime anecdotal claims that the dirtier snow is, the faster it melts.

''That has enormous implications up and down the line,'' Painter said. He said it's important because when the snow cover dissipates earlier than it should, the ground is exposed at a time when the sun is highest in the sky. This can hurt the local ecology.

''That has some impact on regional climate,'' he said. ''We're seeing a 1.5 degree Centigrade temperature increase.''

Painter, a recent addition to the university's geology department, is now studying the Wasatch Range. He says the snowpack there is under serious assault from dust and soot. Wasatch canyons provide most of Salt Lake City's water and are economically significant for winter recreation.

''If it's possible to clean up the snowpack, we can buy significant time to increase snowpack duration,'' he said. ''We have enormous amounts of research to do. I look forward to doing it over the next decade.''

Painter said dust's effects on snow are a global problem. The disappearance of central Asia's Aral Sea, for example, magnifies ecological devastation by sending plumes of dust off the dry lake bed. The dust blows east and settles in China's Tienshan mountain range, where it disrupts the snowpack's hydrologic cycles.

Old lake bed sediments document changes over time, in the way historic weather patterns are written into tree rings. Reading these sediments reveals a surge in dust emissions around the world, Painter said.

from: The Salt Lake Tribune, http://www.sltrib.com