Parameter Tree:
EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > GLACIERS/ICE SHEETS > FIRN

Definition:
Rounded, well-bonded snow that is older han one year. A permeable aggregate of
small ice grains with densities greater than 0.55 up to 0.82 where begins
glacial ice. (Glossary of glacier terms/Northeastern Illinois University)


Reference:
Glossary of Glacial Terms, Northeastern Illinois University
http://ebeltz.net/glacier/glacglos.html