Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS CMG InfoBank: Snow Line

Skip navigational links
Loading
Dictionaries: Our Mapping Systems   The USGS and Science Education   USGS Fact Sheets   Topics   Keywords   Data Dictionary   Metadata Dictionary   Computer Terminology   Digital Formats  
InfoBank Terms: Activity ID   activity overview   crew   digital data   formal metadata   lines   metadata   NGDC   port stops   project/theme   region   ship   stations   time   virtual globe   year  
Data Types: bathymetry   biological   geochemical   gravity   ground penetrating radar   imaging   LIDAR   logs   magnetics   metering equipment   navigation   samples   seismic   total station   definitions disclaimer  
Data Formats: ARC coverage   E00   FGDC metadata   gridded/image   imaging   material   scattered/swath   Shapefile   vector/polygon  
Comment: 07:38 - 08:59 (01:21)
Source: Annenberg/CPB Resources - Earth Revealed 23. Glaciers
Keywords: glacier, ice, "glacial melt", "valley glacier", "zone of accumulation", "zone of wastage", "snow line", season, firn, silt, snow, "lower elevation", "glacial retreat", snout

Our transcription: Regardless of type, all glaciers move ice from its point of origin to areas where it melts.
In a typical valley glacier, ice builds up year after year at the head of the glacier in the so-called "zone of accumulation."
Down-slope the ice melts away faster than it can build up at that lower, warmer altitude.
This is the so-called "zone of wastage."
These two zones are divided by the "snow line," which can actually be seen on some glaciers during the summer months.
Down-slope of the snow line melting snow exposes old, silty firn in the zone of wastage.
Up-slope the glacier is permanently covered with fresh white snow.
The snow line shifts up or down the surface of the glacier from year to year.
During cool years the snow line lies at lower elevations than in warm years.
If ice moves into the zone of wastage faster than it melts away, the snout of the glacier will advance farther down-slope.
But if not enough moves into the zone of wastage to compensate for melting, the snout of the glacier will retreat up-slope.

Geology School Keywords
Skip footer navigational links

Coastal and Marine Science Centers:  Pacific   St. Petersburg   Woods Hole  
InfoBank   Coastal and Marine Geology Program   Geologic Information   Ask-A-Geologist   USGS Disclaimer  


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://walrus.wr.usgs.gov/infobank/programs/html/school/moviepage/21.01.08.html
Page Contact Information: InfoBank staff
Page Last Modified: Thu Oct 31 04:27:46 PDT 2013  (chd)