Dirty snow - another part of
the global warming chain of events |
Last year saw snow around Colorado's San Juan Mountains melt a month earlier than is usual. It was blamed on dust - dust blown hundreds of miles from severely dried out desert areas of Arizona and New Mexico.
The dust, less reflective than snow, has reduced the areas overarching reflectivity, which permits greater amounts of the sun's natural warming energy, and the resultant melt. Scientists believe this is similar to the effect of dark soot falling on Arctic snow, which has sped up melting there as well.
"The connection between dust and lower snow reflectance is already established, but the amount of impact measured and modeled in this system stunned us," said study team leader Tom Painter of the University of Colorado at Boulder's National Snow and Ice Data Center. "The fact that dust can reduce the snow cover duration so much—a month earlier—transforms our understanding of mountain sensitivity to external forcings." –Yahoo NewsEight total dust deposition events occurred in 2006, a rise from only three or four between 2003 and 2005, say the study's writers, as explained in the June 23 issue of Geophysical Research Letters.
As global warming proceeds unchecked, the predicted worsening of droughts in the west is expected to make the situation snowball (you should pardon the expression).
"Recent studies agree that with global warming, the Southwest will be warmer and drier," Painter said. "Enhanced dust deposition is likely, further shortening snow cover duration.""Ultimately, a warming climate and the dust it generates will affect river run-off and soil moisture in the mountains," he added. "Not only in the Western United States, but across many of the world's mountains." –Yahoo News
