Minimum snow and ice coverage for GNP, 2003-2015

To determine minimum coverage of perennial snow and ice cover for Glacier National Park, the minimum extent of glaciers and multi-year snow features were digitized from satellite imagery (10-meter NAPP 2003, NAIP 2005, and NAIP 2013, and 30-cm resolution, multispectral, pansharpened Digital Globe WorldView satellite imagery collected in late summer and fall 2015). Features were digitized in ArcGIS version 10.2 using a Wacom Intuos 4 digitizing tablet. Snow and ice features were classified as glacier, large ice mass, or perennial snow/ice. Glaciers were based on current, named glaciers. Remnant ice features not large enough to be classified as glaciers, but showing evidence of crevasses, were classified as large ice masses. Any other [...]