Monday, February 3, 2014

Episode 199 (2-3-14): Snow and Ice Follow Physics and Chemistry

Click to listen to episode (3:00)

TRANSCRIPT


From the Cumberland Gap to the Atlantic Ocean, this is Virginia Water Radio for the week of February 3, 2014.

This week, we feature more mystery sounds.  Have a listen for about 40 seconds, and see if you can guess two basic sciences that are hard at work when winter turns the landscape white.

SOUND.

If you guessed physics and chemistry, you’re right!  You’ve been listening to a snow shovel, salt pellets, and NOAA Weather Radio comments on January 29, 2014, about melting, blowing, and refreezing potential after an Appalachian snowfall.  The impacts of a snowfall—on transportation, recreation, and water supplies—depend on weather conditions interacting with physical and chemical properties of water and of surfaces and substances in contact with the snow.  Key properties include the melting point of water with and without dissolved substances, such as salts; the ability of ice crystals to form various shapes, affecting the how much water any given snow contains; and the capacities of different colors and substances to absorb or reflect light.  These factors affect how energy from sunlight or air is absorbed and transmitted by snow and by adjacent substances and surfaces.  Energy interactions, in turn, determine key snow impacts, like how fast the snow will melt, how much water will result from that melting, and whether that water will evaporate or refreeze.  Water physics and chemistry can be complicated, but their effects are as basic and practical as choosing the best time to shovel the walk.

For other water sounds and music, and for more Virginia water information, visit our Web site at virginiawaterradio.org, or call us at (540) 231-5463.  From the Virginia Water Resources Research Center in Blacksburg, I’m Alan Raflo, thanking you for listening, and wishing you health, wisdom, and good water.

SHOW NOTES
 
[All Internet addresses mentioned were functional as of 2/3/14]



A sun-exposed sidewalk after snow-shoveling in Blacksburg, Va., at 8:30 a.m., January 29, 2014.
Sunlight flecks on a snow-covered sidewalk in Blacksburg, Va., at 9 a.m., January 29, 2014.


Acknowledgments: The National Weather Service (NWS) comments on snow-melting potential on January 29, 2014, were recorded by Virginia Water Radio from the broadcast that morning by NOAA (National Oceanic and Atmospheric Administration) Weather Radio, WXL 60 from the NWS’ Blacksburg, Va., Forecast Office (information is available online at http://www.erh.noaa.gov/er/rnk/NWR.html).  Thanks to Kevin McGuire, Virginia Water Resources Research Center, for providing advice and information for this episode.

Sources and more information: Information on snow physics and chemistry was taken from the following sources:
*Field Guide to Snowflakes, by Ken Libbrecht (Voyageur Press, St. Paul, Minn., 2006);

*The Chemistry of Everything, by Kimberley Waldron (Pearson Prentice Hall, Upper Saddle River, N.J., 2007); see p. 266 for “Why is Salt Used to Melt Ice on Wintry Roads?”

*The Snow Booklet: A Guide to the Science, Climatology, and Measurement of Snow in the United States, by Nolan J. Doesken and Arthur Judson (Colorado State University Department of Atmospheric Science, Fort Collins, Colo., 1997); and

*Winter: An Ecological Handbook, by James C. Halfpenny and Roy Douglas Ozanne (Johnson Publishing Company, Boulder, Colo., 1989).

Information on the SNOTEL (“snow telemetry”) data system of measuring snow pack and its water equivalent in the western United States is available from the National Resources Conservation Service (NRCS), online at http://www.wcc.nrcs.usda.gov/snow/.


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