Snowpacks melting sooner

    Why are mountain snowpacks melting sooner these days?
 
    Part of it may be climate change associated with increased levels of carbon dioxide in the atmosphere, but there's something else in the air -- dust (a/k/a airborne particulate matter).
 
    Snow reflects sunlight quite well, as evidenced by the blinding glare it produces and the phenomenon of snow-blindness.
 
    Put a layer of dust atop the snow, though, and more of the sun's energy is absorbed, rather than reflected. The absorbed solar energy makes the snow melt faster (see our story "Dust and Snow").
 
    And in recent years, as shown by sediment layers in western ponds and lakes, humans have greatly increased the amount of dust in the air, leading to earlier melting.
 
    This has major implications for water managers who rely on alpine snowbanks for storage, and there's more in this article.